Social network services allow people to come together online around shared interests, hobbies or causes. For example, some sites provide meeting organization facilities for people who practice the same sports. Other services enable business networking (Ryze, XING and LinkedIn) and social event meetups (Meetup).

Some large wikis have effectively become social network services by encouraging user pages and portals.

Anyone can create their own social networking service using hosted offerings like Ning, grou.ps or rSitez or more flexible, installable software like Elgg Social Networking Engine, Anahita Social Networking Engine^[2], Jcow, BuddyPress, SocialEngine, Oxwall, phpFox, Status.net or Concursive's ConcourseConnect.