European laws coming into action on the 26th of May state that "explicit consent" must be gathered from web users who are being tracked via text files called "cookies".
The directive dealing with cookies was drawn up in an attempt to protect privacy and, in particular, limit how much use could be made of behavioural advertising which involves people being tracked across websites, with their behaviour used to create a profile that dictates the type of adverts they see. The EU directive demands that users be fully informed about the information being stored in cookies and told why they see particular adverts.
Excluded by the directive are cookies that log what people have put in online shopping baskets.
Read more: EU cookie law enforcement (26/05/2011)