It's a fair point and something we've often considered within our own resource limits.
Although there is, as Marcin points out, a lo-fi version of the forum for mobile devices with slow connections such as that provided by GPRS it's worth noting that when we did the recent upgrade the site was designed to be fully W3C compliant for HTML and CSS. We also decided not to use Flash.
The consequence is that although the site is quite demanding in terms of page loads the site operates on practically all standards compliant browsers that are now finding their way onto most smart phones (works great on an iPhone for example), PDAs, games consoles and of course traditional PC's. In terms of page load times we would hope that the mobile web for phones via EDGE, 3G and HSDPA will improve the experience considerably but granted this does make it a bit elitist for the time being!
