There is a clear distinction between active and passive tracking. The law applies to active tracking, whereby something is stored on a user's computer and this something is subsequently retrieved/read. Cookie tracking is a form of active tracking. Passive tracking, whereby nothing is first stored on a user's computer, is not covered by the law. Indeed, it is difficult to see how it could ever be covered.

If tracking is done on the server, how would anyone know/be able to prove that it is taking place?