We try to keep things as easy as possible for you, that's why we try to hide details that simply don't matter for you. By following a contact, deal or project, we know this page is important for you and we'll let you know if something important happens on this page. It's similar to social networking sites where you of course only see what your friends and peers are doing, not just everything that's happening on Facebook for example.
So how do you follow a person, company, deal or project? You follow a site if you ...
created it
interacted with it (eg. wrote a note)
manually clicked the follow link on the page
have been notified by a colleague writing a note that is of interest for you.
Once you click within the add a note area on any page, you'll sometimes see colleagues being already checked to get informed. That's because those colleagues are following the page you are writing on.
You may unfollow a page any time by clicking the unfollow link on the page.