Hello, Below is the description of The tracking settings for Firefox Tracking

• Tell sites I do not want to be tracked: Choosing this option will tell websites that you wish to opt-out of tracking by advertisers and other third-parties. Honoring this setting is voluntary — individual websites are not required to respect it.
• Tell sites that I want to be tracked: Choosing this option will tell websites that you want to be tracked by advertisers and other third-parties. You should be aware that many companies build a profile of sites you visit. Checking this option means that you are ok with that.
• Do not tell sites anything about my tracking preferences: This is the default setting. Choosing this option will not tell websites anything about your preferences. You should note that this does not mean that you will not be tracked. In fact it's effectively the same as the previous option, and you are likely going to be tracked.

For more information, please see this Settings for privacy, browsing history and do-not-track

For more information on not being tracked, see this How do I turn on the Do Not Track feature?.

Also, you can use a addons called lightbeam to see who is tracking yourself. You can add to your Firefox from Here. Lightbeam for Firefox

Note that this only involves sending a DNT=0 header (Tell sites that I want to be tracked) or a DNT=1 header (Tell sites I do not want to be tracked) to the server as part of the HTTP request headers. If "Do not tell sites anything about my tracking preferences" is selected then this header is omitted and a DNT header isn't send.

It is entirely up to the server to do anything with this request.

• http://www.mozilla.org/en-US/dnt/