Okay... Let's get this straight: People use the Instant Messenger their friends use. It's no use using (for example) AIM, if 99% of your friends and family use MSN.
Unfortunately, MSN is the most dominant Instant Messenger in Australia (especially with young people). This is the case because Windows is now (and has been for some time) bundled with MSN/Windows Messenger, and for convenience, users simply choose to use it (along with Windows Media Player, too).
Being in a high-school environment in which students require laptops, I was the first to bring in (and show the IT Department it was possible to use) an iBook. Since then, I have converted a dozen or so people to switch to a Mac. iChat, quite simply, is awesome for LAN environments, because of Rendezvous. The AV features I find superb, also.
However, because my school uses an HTTPS proxy server, I am unable to log into the MSN servers, while Windows users with MSN are able to do so. Why is this so? Because MSN for Mac (including 4) does not include the ability to use an HTTPS proxy.
I do not believe MSN 4.0 deserves a .0 release, simpy because it's 'new' features do not justify one.
I resent having to make excuses to Windows users when they ask me why they can't have a video (or even voice) chat with me, or play an MSN game with me, or look at their user-picture, and so on.
The differences between MSN 4.0 for Mac and MSN 6.1 for Windows are immense. Even third-party products for Mac can't match the feature set of the Windows version.
I am annoyed... to say the least. And converting 130+ people to use another protocol is simply impossible.
The state of Instant Messaging on the Internet is appaling. We need a proper, open protocol, that people are actually compelled to use.