RSS feeds - where did they come from?

Hi

I have a customer where a lot of users claims that suddently they have A LOT of RSS feeds in their Outlook 2007 and no one did anything.

Is it possible for RSS feeds to add themself? Or is it possible for others to add feeds for other users?

I have no clue where to start here.

The most of the feeds comes from their local Sharepoint site.

BR
Steen