Vyew is a browser based web conferencing solution that supports browsers on Windows, Mac & Linux. You can use the hosted version or get the enterprise appliance to setup an on-premise version. It has screen sharing, application sharing, remote control, recording, chat, whiteboard, voice notes, polls, screen capture, session scheduling and telephone conferencing. It also has built-in support for VoIP and your computer webcam. For more control, it provides both a server-side and client-side API, so you can enhance the application or build your own integration modules. The free version supports up to 10 participants.

via Top 7 Dimdim Alternatives | blog.teamextension.com.