All, forgive the tech babble in advance...
novice_btm, I agree with you. Yes it does leave certain users out of the mix when technologies diverge and that's no fun.
PInkSteel, I'm afraid you are off base. No, using Microsoft is not at all like shopping only at wallmart. I'm a software engineer and I assure you that MS technologies are very solid in the web space, DB space, and in general. The type of technology we used, the .NET framewok, (which does aim to support netscape and firefox through ASP.NET by the way) is more often reserved for corporate and big budget operations where as PHP and other open source technologies (which are free) are more widespread for forum type sites.
The issue with why we don't support Firefox isn't so much Microsoft in specific, rather it's that IE and Firefox actually interprit design objects differently. This doesn't impact you if all you're doing is something very vanilla, but our design is more intricate than that, and being that 85% of the public uses IE we decided to launch as IE only. We will circle back around and fix that.
If you look at Google and Yahoo, and any number of sites that work across all browsers you'll find that a) they all look sort of the same, and b) the design is very simple. Where IE really offers the sky as the limit for developers, firefox\netscape is a lot more limiting, so developers have to make a choice vanilla and support all, complex and support all (more work), complex and support just IE.
The best business dessision is generally the first one, but the site my team and I put together, as exhibitionists, is a labor of love as much as a business investment. We simply didn't want to do another vanilla site. We decided to go complex and support all, but the more work part will take a little time for us to allow firefox users.
To make a long story short however, downgrading your vision to create a vanilla site that will work with every browser on launch feels much more like shopping at Walmart to me than using the latest programming technologies to produce an experience that, while it may be less accessible, is unique. To me the latter sounds much more like shopping designer brand name.
I do understand that it is frustrating though to not have your browser supported, so again we're fixing that, I just had to correct that Wallmart statement. | 
