It started in 2008, with just Interplay and Codemasters. For a little while in the beginning there was a secret code you needed to enter to log on - that was during the first phase of the close beta. The forum looked more-or-less as it does now, but without that big white bar (instead there was a grey bar statically positioned at the top of the page, without drop-down menus), and I don't recall there being a "fat footer" in those days. The front page looked almost completely different.
The shelf looked the same but worked somewhat differently - you could rearrange games as you wanted and could leave spaces (I don't think you can do that anymore). The shelf and the catalogue were loaded in one go rather than bit-by-bit in ajax as they are now.
New games didn't appear as regularly as they do now but I seem to recall there being at least one new game announcement and one "coming soon" each week. There were specials every weekend from what I recall, just like now - except that it was usually an Interplay promo.
All-in-all, it was similar enough that if you saw the old site you'd probably still recognise it as being the same site as the one today, just with a lot if little things that changed over the years.
Oh, and gdfsgsdfhgsdfghsdgfh.