co-op was first by a considerable margin. Both programs have their uses, and you'll find that many people here use both.
Ones a link network of permanent links (LV) and the other is a semi rotating advertising network (coop). Different strokes for different folks
heh personally I'd recommend LV for a long term strategy, but I never really got into the COOP much..
I have used a lot of link vault and have yet to see much bonus outside of msn but being that it has been trickling on for months now , and most if it is on new sites its probably too early to tell.