Solutions designed for business web based collabloration and used by 75% of the worlds corporations can't be wrong.
There's several things wrong with that statement. You really should've stuck to the original one -- I'd be willing to bet that a solution designed for business use would be much more reliable than one designed for gaming use.
1) This isn't web based collaboration. It's much more akin to IM or IRC than that. Loosely connected systems, a wide range of things you want to be able to monitor, and the ability to search based on those things (for, oh say, friends, open servers, servers running particular settings, etc.) are all issues that don't exist for "web based collaboration". At least not in any of WebEx's current tools as best I can tell.
2) Internet Explorer is used by 95% of people world wide, so it can't be wrong. Cough.
3) WebEx only has 11,000 customers -- both corporations and individuals. You're telling me that there's fewer than 16,000 corporations in the world? Maybe you meant 75% of Fortune XXXX corps... which is not a statement claimed on their website. The closest you get is "now holds 67% of the marketshare in online meetings and Web conference services".