Omegle - Omegle is one of the most popular online chat website allowing user to communicate with anyone without registration.
Diigo - Diigo is a powerful research tool and a knowledge-sharing community
Emerald Chat - An omegle alternative on the web with several enhanced features.
Unmark - Hosted bookmark management app
BlaBla.Cam - BlaBla.Cam is basically Omegle or a Chatroulette reimplemented with the latest web technologies. It offers a simple and lightweight user interface that works on both computer and smartphone, and which can optionally be installed as an application.
Shaarli - Shaarli is a minimalist link sharing software you can install on your own website