So I'm making use of the group space on the boards. It's a lot of fun for me but it has been a challenge to get the players on board. I know they like the idea, it's just a matter of them taking time out of their day to sign up for another message board and follow another set of digital updates.
I did a lot to make the group attractive. I'm keeping all session recaps in blog posts so they are easy to refer to later (my players tend to forget things they did previously). I'm trying to start discussions in the forums (I don't expect this feature to take off with my group, though you never know). And the Wiki is where I expect them to derive the most benefeit. I figure I can use the wiki to give background info on the world that a person living there would know but might not come up in play. I've also tried to imbed adventure hooks in there. We'll see how that goes. I hope the players take to it.
Finally the calendar. I really wish this worked better. I tried sending out invites to the next session but I don't think they went out. We'll have to wait and see on that one. Still, it's probably the most useful feature for me (if it works).
The other thing I've been using for four or five sessions now is DDI. I LOVE DDI. I look back at those first half a dozen sessions without fondness. I had to write out all monster stats or bookmark the pages and juggle books all session. Now I copy out of the compendium and paste into an Excel document. Then I preroll about two dozen attacks (with the bonuses added in). I've dramatically reduced the monster turn times. It's great.