I have to admit having been a little unconvinced by social networking sites, they seem to only offer a poor man’s version of a web presence, photo sharing that pails besides Flickr, blogging that can’t touch WordPress et al. So my MySpace presence is only because I use MSN Messenger and it gives me a chance to create more links back to my own site – verging on anti-google-bashing. I picked up on LinkedIn purely because it provides a professional presence (something that some may suggest my domain name might not provide).
Then I signed up to Facebook, more out of curiosity, and a bit more more anti-google-bashing. But the provision of the APIs has made a world of difference. I can integrate my Flickr and LinkedIn profiles along with a dozen other best of bread solutions.