How facebook tracking your activity on web?

Today's main praivacy issue that facebook are tracking peoples activity even they are logged out from facebook!!. by the issue a german minister tells to colleagues to avoid facebook. this means the company facebook are used to track peoples actvity accross the web for marketing purpose. but thinking of other company like google they are bot tracking activity like this. the question is why facebook is doing this?.

Recently facebook released the methord used for tracking peoples activity in facebook and out of  facebook.

facebook track activity for different way for for different members.

             1. Who? have signed in.

             2. who? have are using now with logged in.
             3. who? have signed out and non members.

for the three types of memebers  first time you visit a acebook page even loging page the company insert a new  cookies file to your browser.after you signed up in facebook page it insert two type of  cookies file to your browser. and you dont setup a an account it will insert only one of the 2  cookies file.

these  cookies file track your activity if you visit a website which is having a like botton or any other plugin from facebook . that record the site you visited, date and time


Facebook keep records of your past 90 days activity and deletes entries older than 90 days, the "Sydney Morning Herald" reported.