Comparison of 7 Web conferencing systems
  Centra OpenCampus LiveMeeting[1] Marratech PictureTalk Live![2] Webex
Vendor Centra Horizon Microsoft Marratech Pixion Elluminate Webex
VoIP      [3]    [4]    [5]
Multipoint VoIP              
VoIP-to-phone bridge            [6]  
Live video (of presenter)    [7]        [8]  
Multipoint live video            [9]  
Moderator/Leader role              
Text chat              
Whiteboard              
Content can be added on the fly  [10]            
Content can be uploaded in advance              
Content preparation tool(s)[11]              
Live application sharing          [12]    
Live desktop sharing              
Sharing Web pages              
Automatic recording to server              
Personal (local) recording              
Mac client              
Full screen view of content        [13]      
Polls              
In-house installation              
Distributing files during sessions[14]              
Breakout rooms              
Shared, on-the-fly screenshots              
Instant feedback (e.g. emoticons)    [15]          
Markup tools              
Private chat  [16]            
Secure (encrypted) communication              
Color codes:
    has this feature/ability
    does not have this feature/ability
    has part of this feature/ability (often with comments to clarify)
    no data
[1]
Formerly: Placeware
[2]
Formerly: vClass
[3]
Unclear. Probably not.
[4]
Optional
[5]
Optional, via 3rd party plugin.
[6]
Via 3-rd party tool
[7]
One-way only
[8]
Through app sharing
[9]
Through app sharing
[10]
Some types of content
[11]
e.g. creating a survey/poll to be displayed during session, or combining different media (images, PPoint slides, audio clips, URLs) into a single, ready-to-use presentation.
[12]
Incuded in desktop sharing
[13]
In "Expert" mode only. Can't be forced on participants
[14]
E.g. to send a Word document to everybody in the session.
[15]
Only yes/no, raise hand
[16]
With Presenters only