I just got a look at SpendView, a financial site for young people. It will compete with Mint (launching tomorrow; hands-on review coming then too) and Wesabe (review) and it shares a core feature: When you let the product download your bank and credit card data so you can track it, it also uses that data to create an aggregate view of how people spend money. Then it lets you compare you outlay on, say, rent, gas, and food, to other people like you. It's social without being personal. (You can ignore the social info if you want, and just use it to tag and track your own spending against a budget.)
Similarly, Cake Financial, also at this event (TechCrunch 40) adds a social angle to investing. It shows you how your portfolio is doing against your peers. Its difference is that you can see individual portfolios (by handle, not actual name) and ape the behaviors of the ones you like.
I never thought of finances as particularly social. Quite the reverse, in fact. That might be because of my advanced years; apparently, the younger crowd, raised in MySpace and Facebook, shares everything, and wants to see what their pals are doing, even financially.