UK Daily Mail 
July 4, 2013
Twitter has announced it plans to start tracking users and the websites they visit.
The site plans to use browser cookies – small files that are placed on people’s computers each time they visit a web page – to track online movements.
Advertising partners will then be able to target customers by either anonymously matching email addresses of users, or by using the cookies collected, to serve more personalised adverts.
In a blog post, Twitter said that the service will be launched in the U.S. but did not say whether it would be rolled out to other areas.