What goals do you have in mind for networking? What do you want to get out of it? For example: do you want to network with people having a certain background, your ultimate goal being to identify and hire best talent for your company?
I, for example, network on websites like workitmom.com for 3 reasons: 1/ to learn what small business owners (or people in charge with growing businesses) are struggling with when it comes to marketing/business growth, 2/ to offer help and an efficient networking platform for these individuals (www.mybeezoo.com - soon to be turned live) and 3/ meet diverse and creative people I can bounce off ideas with and help each other through that. More often than not, few of the people I meet through work or networking end up becoming my friends ... which is a nice perk
Depending on what you wish to get out of it, members of this group might be able to suggest some appropriate networking sites.
All the best,