Create your own social network
If none of the existent social networks satisfies you, you can create your own online community. The important thing is how to create it and how to serve its interests. You can opt for an existing community, and add new options and needs, or build one, based on certain interests, for people with common passions, who are not connected to each other: gamers' community, travelling lovers' community etc.
The advantage of an existent community is that it already has a number of people who daily enter the site. The easiest formula is to make a blog; once you have readers and people to contribute, you have a community and can start thinking about extending.
To create such a project, there are certain sites that offer software platforms to administrate the social network. SocialEngine and Ning are such sites, which perceive taxes of 4euro/month, respectively $2, 95/month. Once the profile is created, you choose whether the network is going to be public or private. In order to earn money out of it, you have to become well known. You must be original and attract people with something new and useful for their social life.