Why create a facebook application now given that there are thousands out there already and facebook has created lots of restrictions preventing the viral growth

Why create a facebook application now given that there are thousands out there already and facebook has created lots of restrictions preventing the viral growth that the earlier apps experienced. Even the new ones like the one released by Yahoo only have 5000 users. It may have made sense in the beginning - Can anyone see any benefit of this now? or is it just hype ?