For something like that I'd usually suggest WordPress with the
FeedWordPress plug-in but since WP2.1.X I've been hearing more complaints about duplicate postings from that specific plug-in.
Although, since adult feeds seem to differ a bit from a standard feed it probably is very dependent on the feed.
This is another type of
WP aggregator plug-in but I haven't tried it yet so i can't say how well it might work
Some non-WP solutions might be
Gregarius or
FeedCMS
I've played around with both a little bit. Gregarius seemd like a pretty good script but since I wanted something that would allow people to submit their RSS feed, rather than having to add them myself, I decided not to use it.
FeedCMS seemed like a very good script but immature in it's development. But it might do what your looking for.