RSS Reader app - subscribe to certain topics?

Is there any function or app out there that will enable me to follow posts? For example, a question that i may have asked a year ago but want to continue following up on in case there is a reply? I have about 20 threads on this forum bookmarked and would like an easier way to keep up with them. I've only seen the availability to check a main page or subforum..but it seems like there should be something else available.

 

yes, i use that sometimes, but to be more specific, i was wondering if there was something like this that would combine posts from different forums that i may be following.

so if i want to check on a post, i dont have to log in, go to my profile, etc.