How do I install ShareMeNot, and which
browsers are supported?
ShareMeNot is supported on Firefox (versions 12.0 and above) and Chrome
(version 17 and above). Using Firefox, click on the “Add to Firefox” download
link on our Download page, and then click “Allow”
to install the add-on. Using Chrome, click on the “Add to Chrome” download link
on our Download page, and then “Install” to install
What is a cookie?
A cookie is a small text file stored on your computer. Most websites set one
or more cookies on your computer when you visit them. Once set, these cookies
are automatically sent to the website that created them every time you visit
that website. The website uses the information in the cookies to remember
information about you (such as which account you’re logged in with or what you
placed in your shopping cart last time you visited this site).
First-party cookies are cookies created by the site you’re
visiting directly (whose address you see in the browser’s address bar).
Third-party cookies are cookies created by any other sites
that may be embedded within the site you’re visiting directly (for example, an
advertisement embedded in another site).
What is third-party web tracking?
When websites other than the ones you directly visit gather information
about you as you browse the web, this is third-party web tracking. For example,
when you visit websiteA.com, the site may embed third party content, like
advertisements from advertisers, buttons from social networks, or web analytics
code from web analytics engines. These third-parties are invisible to you when
you visit websiteA.com — the web page looks just like a regular web page
to you. But these third parties gather information about your visit to
websiteA.com (and to any other websites on which they are embedded).
These trackers generally set a cookie in your browser, which is simply a
small file that contains text, often including a unique identifier. This
identifier might identify you anonymously or, if you are logged in to the
tracker’s site, as a specific user of that site. Whenever a request is made to a
website, including the embedded third-party trackers, your browser automatically
attaches the cookies to the request. This mechanism lets the tracker that set
the cookie identify you again and thus link your visits between websites.
As a concrete example, suppose websiteA.com and websiteB.com
both embed ads from some advertisement company. When you visit
websiteA.com, the embedded advertisement will set a cookie with a unique
identifier on your computer. When you visit websiteB.com, the embedded
advertisement will send that cookies—which includes your unique identifier—back
to the advertiser. This allows the advertiser to link your visit to
websiteA.com with your visit to websiteB.com.
Why do some people consider web tracking a
By tracking you across the web, a tracker can compile a profile of your
browsing behavior, generating an accurate profile of you even if they are
tracking you anonymously. Some people are uncomfortable with third parties
compiling this much information about them, often without their knowledge. For
this Wall Street Journal article discusses the privacy concerns
surrounding web tracking.
Why isn’t it enough to block third-party
A common misconception is that you are free from tracking if you disable
third-party cookies or opt into “Do Not Track”. This is not actually true in all
When you block third-party cookies, any website that you don’t directly
visit cannot set cookies in your browser. For example, if you visit
websiteA.com and it embeds ads from advertiserX.com,
advertiserX.com will not able to set cookies. Blocking third-parties
cookies can help with tracking by third parties whose sites you never directly
visit (like advertiserX.com in this example).
However, blocking third-party cookies cannot always help with
tracking by third parties whose sites you do visit directly, such as
Facebook, Google, Twitter, etc. This is because these sites set first-party
cookies when you visit them directly and can then use these cookies to track you
as you browse the web. This latter category of trackers—ones that can set
first-party cookies—is the one that ShareMeNot targets.
Note that while these websites can set cookies, not all browsers allow them
to read these cookies when they are embedded as third parties. For example,
blocking third-party cookies in Firefox (but not in Chrome) prevents this type
of tracking—however, it prevents some of the buttons from functioning correctly.
ShareMeNot aims to prevent tracking by these buttons while allowing them
to function correctly.
(Note also that there are other ways that third parties advertiserX.com can
track you without third-party cookies, such as using
mechanism, Flash cookies, or other tricks. ShareMeNot does not address
Why can’t I just use NoScript or Ghostery or
Disconnect any of these other anti-tracking extensions?
NoScript, Ghostery, and Disconnect are all great browser add-ons that
can be used in conjunction with ShareMeNot. They help protect you from
third-party tracking by allowing you to block advertisers and other trackers.
However, all of these add-ons completely block the tracker that you choose to
block. This means, for example, that if you block Facebook, the “Like” buttons
will appear to have disappeared from the web. This prevents Facebook from
tracking you via the “Like” button, but it also prevents you from clicking any
“Like” buttons. ShareMeNot is designed to protect you from tracking while
allowing you to choose to click the button (thereby allowing you to “Like”,
tweet, or “+1” a page, but with the necessary side-effect of allowing the
creator of the button to track your visit to that page).
What does ShareMeNot do differently, and how
does it work?
ShareMeNot blocks requests to the trackers completely, but it replaces the
real buttons with local versions of the buttons. When you click on one of these
stand-in buttons, ShareMeNot either emulates the normal button by opening a page
with sharing options (for Twitter, Stumbleupon, LinkedIn, and Digg) or reloads
the normal button (for Facebook and Google). Thus, ShareMeNot makes no requests
at all to trackers until you choose to click on a button, keeping your IP
address and other information from being sent to the trackers until you click a
Optionally, you can ask ShareMeNot not to replace the social buttons, but simply
to remove cookies from requests the browser makes while loading the real buttons.
Choose this option (by unchecking the "Replace social buttons with local versions"
box in ShareMeNot's settings) if you notice that ShareMeNot causes problems with page layout.
It is less privacy-preserving, because the requests made while loading the real
buttons reveal information like your IP address, browser, and other information
that can also be used to track you.
If a website can track me, does that mean it is
developing a profile of me?
Different websites have different privacy policies with respect to the data
they collect about you. Some explicitly use the data they collect to track you
(for instance, for the purpose of targeted advertising). Others state that they
use the data only for diagnostics and discard all data after a short period of
Google). ShareMeNot does not distinguish between trackers with
different privacy policies. Rather, it aims to prevent the sites that provide
the buttons from having the ability to track you, regardless of what they
actually do with the data they collect via the buttons.
Can Facebook’s “Like” Button and other buttons
track me if I’m logged out?
Yes, because when you log out of a tracker's site, this does not necessarily
delete the cookies that the tracker has set on your computer. This means that
while the website (like Facebook or Twitter) treats you as logged out, it can
still read the cookies that remain on your machine. The remaining cookies may
include unique identifiers that continue to identify you to the tracker.
Furthermore, websites may set cookies when you visit them even if you do not log
in and have never logged in. In some cases, these cookies contain unique
identifiers that can be used to track you. (As a reminder, the fact that a
website is tracking you does not necessarily mean that it is creating a profile
How do I use ShareMeNot?
After you install ShareMeNot, you can continue to use your browser as usual.
It will automatically protect you from tracking done through any of the
supported buttons (see below for a list). If you wish to click on one of these
buttons (to “like”, “tweet”, or “share” something), ShareMeNot will
automatically allow the tracker to identify you so that the sharing action you
expect will complete normally. Once you click on a button, you opt in to allow
the corresponding tracker to track you on that site only. This is necessary if
you wish to use the button for its intended purpose, such as to “like” or tweet
ShareMeNot for Firefox has an icon in the add-on bar. ShareMeNot for Chrome
displays an icon in the location bar whenever a tracker is blocked on the page
you are viewing.
In the popup menu that appear when you click the icon in either browser, you
can allow particular buttons on this page. You can do so by
clicking on the icon and then clicking on the name of the tracker whose buttons
you wish to allow; an option to allow the buttons and reload the page will
How can I tell if ShareMeNot is working?
You can check if ShareMeNot is working on the test page, which includes instructions for
determining if the add-on is working correctly. Remember that ShareMeNot does
not remove buttons from the web page. Rather, it prevents the tracking cookies
from being sent until you choose to interact with the buttons. This
means that you will still see buttons even when ShareMeNot is working
correctly. If you have the "Replace social buttons with local versions"
option set, these buttons may appear slightly different from the normal
buttons, as they are local stand-ins provided by ShareMeNot.
Which buttons does ShareMeNot support?
ShareMeNot currently supports the following buttons:
Facebook’s “Like” button
Stumbleupon’s share button
LinkedIn’s share button
Twitter’s “tweet” button
Google’s “+1” button
Digg’s share button
AddThis's share buttons
Can ShareMeNot be extended to support other
Yes, ShareMeNot can be extended to support most similar buttons; how
complicated this extension would be depends on how the button is implemented by
the tracker. If you’d like to see a particular button supported, please let us know (but realize that this is a research
project and that we may not be able to respond to all requests).
How fragile is ShareMeNot to changes in the
ShareMeNot works by recognizing the requests your browser makes to the
trackers to display the button, as well as the requests your browser makes when
you click the button. If a tracker changes the format of these requests
substantially, ShareMeNot may no longer function correctly for that button. If
ShareMeNot fails, it is designed to not break the buttons; rather, it just
allows the buttons to display and you to be tracked as you would without
Does ShareMeNot prevent all tracking by these
ShareMeNot prevents tracking that is done via the buttons listed above.
However, there are still other ways that some of the providers of these buttons
can track you. For example, Facebook provides a broader set of social
plugins such as a “recommendations plugin” or an “activity feed”. If another
website has embedded one of these social plugins in addition to the “Like”
button, ShareMeNot does not necessarily prevent Facebook from tracking you on
that site. (However, it will successfully block some Facebook plugins other than
the “Like” button—you may notice that a Facebook button has been blocked even
though you don’t see a “Like” button.) There may also be other buttons not
supported by ShareMeNot that allow these trackers to track you—if there is
something in particular that you would like to bring to our attention, please let us know.
the test page or elsewhere on the web.
they are still requested from the trackers. ShareMeNot prevents the cookies set
on your computer by that tracker from being sent with that request, so you still
cannot be tracked. However, since the buttons do not function without
Why isn’t ShareMeNot blocking this
If ShareMeNot does not appear to be blocking a particular button, you may
have authorized this tracker to track you on that site.
Navigating away from and back to the page will clear authorized trackers.
Furthermore, some custom buttons on web pages look like the buttons
supported by ShareMeNot but in fact make no requests to the trackers until you
click on them. ShareMeNot does not need to block these buttons. If you do
believe you have found a button that is not correctly blocked, please let us know.
ShareMeNot is breaking the layout of
If you have the "Replace social buttons with local versions" option enabled,
ShareMeNot replaces all social buttons with local stand-in versions. Because
ShareMeNot sometimes has to guess about the size of the button that would normally
have loaded, ShareMeNot can make mistakes that affect the layout of the webpage.
To fix this problem, you can either allow tracking only on the current page,
or you can change ShareMeNot's settings by unchecking the "Replace social buttons
with local versions" box. If this box is unchecked, ShareMeNot will load the real
buttons, but will protect your privacy by removing cookies from the requests made
while loading those buttons.
Why do I have to click some buttons
ShareMeNot must load the Facebook “Like” button and the Google “+1” button
before you can really click on them, so you will first need to click the
ShareMeNot stand-in button and then click again on the real button.
Unrelated to tracking, we do recommend that you enable secure browsing for
your Facebook account (on Facebook, check the “Secure Browsing” box under
Account > Account Settings > Account Security).
I’m using Firefox 4 (or later) and can’t
find the ShareMeNot icon in the status bar. Where is it?
The add-on bar is not visible in Firefox 4 by default. Go to View > Toolbars
> Add-on Bar to enable it.
Why are buttons displaying incorrectly,
even after I disabled ShareMeNot?
Some versions of Firefox have a bug that causes
elements to display incorrectly. Because many of the
elements, you may be more likely to encounter
this bug when testing ShareMeNot. You can reload the page properly using the
keyboard shortcut Ctrl+F5 (or Cmd+Shift+R on Mac OS X), which refreshes both the
page and the cache.
If you see similar problems in ShareMeNot for Chrome, you can use the same
technique to reload both the page and the cache.
ShareMeNot isn’t working on my
First, check for updates to ShareMeNot from the Firefox add-on menu (Tools >
Add-ons) or the Chrome extension menu (Wrench button > Tools > Extensions), and
make sure that ShareMeNot is enabled (in the same menu). If this doesn’t work,
try uninstalling and reinstalling the add-on. If ShareMeNot still appears not to
be working, please let us know.