It is fantastic to see IE8 up the ante on concurrent connections from 2 to 6. I would love to know how they made the call for 6. It sounds reasonable. You don’t want too many else you could end up sucking down so much content at once it could freak out the browser (e.g. imagine a bunch of video on a high speed line).
This should mean, for some situations, that you may not need to deal with www1, www2 type hacks to split up your domains. Of course, sometimes you will still run into the limit and it will be required.
I do wish that Twitter would up their ante too. Maybe not by changing the 140 char limit itself, but maybe by supporting #hashtags so they don’t “take up the room” and instead get moved down below to the metadata layer etc.