PlayByPlay is a collaborative web browsing system that works through instant messaging. This video shows a demo of most its important features. A textual description can be found in:
Heather Wiltse, Jeffrey Nichols. "PlayByPlay: Collaborative Web Browsing for Desktop and Mobile Devices," In Proceedings of CHI 2009. Boston, MA. April 4-9. pp. 1781-1790. (jeffreynichols.com/papers/p1781-wiltse.pdf)
Work done at IBM Research - Almaden in 2008.