Good comprehensive article on web conferencing in education. Unlike other software sectors, there's never been a runaway leader in web conferencing. The most effective solutions tend to be too expensive for casual use, and those that are free or affordable don't have the fidelity required for professional use. Most conference systems are hosted (or as we say today, provided as cloud services) though on-premises solutions have been growing. And the key improvement in recent years has been "convergence of synchronous and asynchronous communications due to greater user demand for better knowledge/content management." GoToMeeting, Adobe Connect and WebEx remain the market leaders. A couple dozen systems also compete.