+1 for the $jobs sub.
I think it would be great if one could create a sub based off a twitter feed. I absolutely hate being forced to login into twitter, and would prefer to read comments here.
Twitter API is pretty easy to work with regarding feeds, and you could have people tip into a wallet balance for the sub, in order to fund continued posting. Popular posts could get picked up by the front page, while unpopular feeds would simply run out of sats and disable automatically.
Twitter feed would be a good start point, which could be expanded to RSS feeds, Youtube, and maybe other APIs. My 0.02.