If you are wondering how good the WebEx product is or how often it is used, here are two interesting facts:

2 Million Users
In March of 2007 WebEx had over 2 million users, and may have even more today.

Bought for $3.2 Billion
Also, in March of 2007 Cisco bought WebEx for $3.2 Billion.

WebEx is a well known product which has been around for quite a while. Get their Free trial here