Right now I'd have to say we're active and we went from a league that NEVER pulled off many trades, to a very active league after we introduced keepers and the ability to trade draft picks was the best thing we ever did for the league. We also have a rule in place your keeper must be someone you actually DRAFTED unless you trade for a player and compensate the owner for the keeper rights as well. It's really been awesome for the league as a whole. We went from 1-2 trades a year to about 10+.
We've now had smart owners trade away talent for next year's picks when they know their season is toast. We have owners in playoff pushes willing to sacrifice early round pics to get that player who will put them over the top. We have people trading for young studs to get their keeper rights.
Anyway, that's my favorite thing. It keeps everyone active, even the bad teams are still active late in the year because they're shopping for next season.