Google+ is a social networking service operated by Google Inc. The Google+ project aims to make sharing on the web more like sharing in real life. Check out Circles, Sparks, and Hangouts, etc.. 

https://plus.google.com/

An international non-profit organization headquartered in Toronto, Ontario, Canada, that connects youth around the world, encouraging them to get involved in improving their local and global communities... 

http://www.tigweb.org/

Users can create, share and discuss blogs, photos, videos and music with others as well as post reviews of movies and books, or share a calendar of events... 

http://multiply.com/

Bebo provides an open, engaging, and fun environment that empowers a new generation to discover, connect and express themselves... 

http://www.bebo.com/

A social microblogging service, built on open source tools and open standards. Allows users to send text-based posts up to 140 characters long... 

http://identi.ca/

Webs helps you make your own free website. Personal, group, and small business websites complete with photos, videos, and ecommerce... 

http://www.webs.com/

Business networking for professionals on XING! Connect to business partners and find jobs, colleagues and employees. Start networking!.. 

http://www.xing.com/

LiveJournal is a vibrant global social media platform where users share common passions and interests. With hundreds of communities built around popular interests, like entertainment, celebrity gossip, music, food, travel, fashion, parenting, pets, and more, LiveJournal users express themselves through creative journaling and lively commentary... 

http://www.livejournal.com/

Ning is the world's largest platform to create powerful, custom social websites. Top organizers, marketers, influencers and activists use Ning to create social experiences that inspire action... 

http://www.ning.com/

The world’s largest online music catalogue, powered by your scrobbles. Internet radio, videos, photos, stats, charts, biographies and concerts... 

http://www.last.fm/