What exactly is meant by Web-Based Instant Messenging (IM)? Instant Messaging (IM) is a form of electronic communication which involves almost real-time communication between two or more users who are all online at the same time. So when we say Web-Based, we mean to say users need not download and install applications on their PCs in order to use the IM services.
Have a look at below link on Web-Based IM Guide.
http://www.masternewmedia.org/news/2007/05/20/webbased_instant_messengers_a_miniguide.htm
I believe they have left out Google Talk unintentionally. We can also run Google Talk as a web-based IM without having to download and install on your PC. We can launch Google Talk either from GMail or from Google Talk official site. I must admit their list is very exhaustive. Out of the many web-based IMs from the list, I have only used MSN Web Messenger, Meebo, eBuddy, and Google Talk.
Complete list
Yahoo! Web Messenger
http://webmessenger.yahoo.com/
MSN Web Messenger
http://webmessenger.msn.com/
Meebo
http://www.meebo.com/
Kool IM
http://www.koolim.com/
eBuddy
http://www.ebuddy.com/
Radius IM
http://www.radiusim.com/
I LoveIM
http://www.iloveim.com/
Snimmer
http://www.snimmer.com/
Mabber
http://www.mabber.com/
Easy Messenger
http://www.mijnmessenger.nl/
IMunitive
http://www.imunitive.com/
Messenger FX
http://www10.messengerfx.com/
Google Talk (Added by Myself)
http://www.google.com/talk/
