Social Networking Software

I've been looking over a lot of social networking software lately, both commercial and open source. They all seem to have their advantages and disadvantages, but I've come to find out they seem like a very steep learning curve to get any of them customized. For instance, a client bought DZOIC Handshakes and while it works great if you are doing a MySpace clone, doesn't work well for business networking. Couldn't find a programmer who would even touch it. What do you all think about the various ones? Is there one that is easy to add new modules too without going back to college?