I guess when you look at all the social networks around on the web today, many cater to the general market and few focus on any niche in particular. They're all great, they all have their pros and cons and I guess that's what makes them so popular.
It's all about sharing, connecting and I guess to a degree, all the major social networks do this well.
Something I might like to see would be more real-time information sharing, something like twitter but with live video feeds? We all have cell phones that allow us to do this with ease nowadays, and I think it would really add a little more something to the social networking scene. Instead of filming something and then uploading it to share one could stream live from their profile where this footage can then be archived for later viewing.