Sharing social sibilance surely

• ScienceStage
• Sgrouples
• ShareTheMusic
• Shelfari
• Sina Weibo
• Skoob
• Skyrock
• Smartican
• SocialVibe
• Sonico.com
• SoundCloud
• Spaces
• Spot.IM
• Spring.me
• Stage 32
• Stickam
• Streetlife
• StudiVZ
• Students Circle Network
• StumbleUpon