List of social bookmarking sites

The idea of making public his favorites and share them with others have been made popular by the del.icio.us website, bought by Yahoo and became delicious.com. It has many imitators.
In fact the idea of social bookmarking was widespread and is found in social networks, and some digg-likes work similarly.

Sites of social bookmarking:

Social network sites can also allow to share his favorites ...

See also