SimSocial is just likeKudos 2, just based in a Sims 3 styled interface and world. It may just be another extension of the Sims franchise but by using Kudos 2 as the basis it is a very good extension. I loved Kudos 2 though it seems I never got around to reviewing it. I thought it was a well made and innovative take on the life-sim genre.
If you enjoy SimSocial it may be worth checking out the demo for Kudos 2 to see what the original game is like.