What's REALLY different about the new site?

Sorry but this might seem a silly question when it obviously looks so different, but how has it changed behind the scenes, is it just a new paint job or has the engine driving it changed?

The old site did have times of crisis occasionally when it seemed to have trouble keeping up with snails, is that likely to happen now?

Would it be possible to post a list of differences to the new front end as compared to the old front end, such as the forums used to be here, they have moved to here … I think this would speed up peoples adoption of the new site, and stop a lot of tears of frustration being shed by people desperately searching for something they know used to be there …

Of course there may already be such a list of differences on the site, in which case I have missed it!

I like the new site, there has obviously been a lot of work and thought put into it, I hope it lasts as long as the old site.

P.S. how do I stop the language thing flashing in the middle of the screen, I am finding it very painful, it is definitely not MS friendly.