I apologize if this is answered somewhere I haven't found yet.

Last year, I was able to fix my settings so that if a new post was added to a thread (say, the thread where rooms are requested & offered), I would receive an email showing the post, allowing me to become aware of all new posts and respond very quickly. This reeeaaallllly helped me find a room and I want to set this up again. I'm not familiar with this new forums setup, so I'm asking 1) is it still possible and 2) if yes, what do I need to do to set it up?

Thank you very much in advance!

That little star up there on the left, right above your post
 

No, all that does is send me notifications on an already existing post. What I set up last year was a way to receive an email notification anytime a *new* Topic post (NOT a response to an existing post) was made. I'm hoping to do this again this year in the search for a room.

The answer is no, currently there isn't a way for you to be emailed when someone creates a new thread (topic).  As kjelstad noted, you can subscribe to a thread to be notified when people make new posts in it.

Unfortunately, you can't change the topic of a thread either so you can't fix the topic of this request.  You might want to make a new thread with a more clear topic, like "Req: Notifications for New Topics in a Forum" or something similar.

Hope this helps.