Most known
Others
- Dopplr (Travel Itineraries)
- Orkut (Social Network)
- Last.fm (Music)
- Tagged (Social network)
- IMDB (Movies)
- Digg (Social News Bookmarking)
- Meneame (Social News Bookmarking)
- Technorati
- Yahoo360
- Tuenti
- YouTube (Videos)
- EBay
- Amazon
- BookCrossing (Share Books)
- Wikipedia
- SlashDot
- Open Source Food
- FriendFeed