Social Networking Sites SEO

I need some suggestions on black hat techniques for promoting a new social networking site. Traditionally I've used bookmarking, directories, articles and keyword optimization for non-social sites. How is a social network site indexed if you are required to be a user. I'm not even sure how a social network site fits into Google's algorithms that user experience is paramount.

facebook / twitter / press releases /articles and xrumer posts. You do not need any seo you need people if its a good site people will spread the word and you will get more people to sign up. But than again what do you consider social networking site?

Yeah if you're talking about Facebook/Twitter, you don't need to "SEO" it, so to say. You need Fans/Followers. If it's networking you're wondering about (i.e how to bring alot of people to my twitter and/or facebook fan page) then there are services/automated software's to do just that. For automated softwares you could use TweetAttacks (twitter) and not sure about a software for facebook. As for services you could find some in the BST section, but i've found much more direct services on sites like elance.com where they'll send thousands of followers/fans to your twitter or facebook, for a fee of course.

The site is a niche market, in particular a medical cannabis forum, so driving the right person to the site will make it successful. Having a mass flood of people won't accomplish that much. When you look up the competition, their forums are open and easily indexed via search engines. In addition, there are tons of back links because their forums are open. Our site requires a login to access any information (i.e. similar to facebook), so I don't think any posts or info will ever be include in search engines. I think there are two ways to grow the site - one is word of mouth which means driving the right people there, and the other is ranking in the top 10 for keywords, such as "cannabis forum" - but not sure how to create that since any webpage on the site can only viewed by a valid and verified user.

Social Media also falls into the place of SEO and has its own special place that falls under the heading of Social Media Marketing. If you site is good and people like it then they would do half of your job for you.