I've used phpfox before, it works pretty well, though to be honest if you want to stand out from the crown I would create your own as this is the only way you'll expand like facebook.
Hey PolakPoncho You are the main Abledating Shill! Please don’t pay attention to Scam posts by Abledating SCAM Company especially to Mr. PolakPoncho. I think he is that Mr. Rudakov!!! The owner of Abledating Scam Mr. Rudakov is a Russian Scammer! He talks slanderously about Wazzum software!!! He will be sued for this slander!
You can use ning to build your own social network! Also I´m able to offfer you the Unselfish Community script, if you want more about, just send me a PM!
have you tried webdate (webscribble.com/products/webdate/)? chameleon? (chameleon.abk-soft.com/demo.php) aspnetdating? There are a lot of them. You just need to chose one which most suits your needs.