I seriously used to meet a lot of chicks MySpace. But we are talking about quantity not quality.
Facebook but it is getting annoying because of the amount of apps and app invites. I don't care about pet fish in fishville, I don't care about your glitter. I don't care I hate Facebook apps. But I do meet some chicks facebook once in a while.
Twitter I'll say is the all out best site for SMM that I have used. And it's super easy to get people to follow and visit whatever links you post.
I sent out like 120 friend requests on Orkut which took me a little over an hour. It yeilded four friends and no click-thrus to my site. No inquiries or messages back. Basically tells me Even in a niche it will hard to make a lot of friends on the site. Even harder than Facebook. I'll say it might be a friend to friend conversation site but for marketing I'm not forecasting a really good return.
For me its facebook because its simple to use and has a lot of user friendly features. Twitter though has been good for my business and i am spending more time on it of late. There is something missing on myspace that has to be worked on very soon if its not to be left behind
When it comes to social networking sites, nothing can beat Facebook. Facebook covers all services like chat, games, entertainment and etc. I guess that's the reason why most of the people are hooked up in this site.