What's the deal with the subscribed threads?
 

I've just found out that my 'Jesu' thread in the non-sonic sounds section has become 'subscribed' - what does it mean?

If you subscribe to a thread, you're notified (by email, I assume) when there are new posts in it.

Although which threads you're subscribed to seems to be random. And you change your preferences so you don't get emails.