The current forums will be set as locked during the beginning of the transition and then will be completely removed toward the end. This means that if there are any old guides, posts or fun things from days of old that you want to see moved to the new forums, you should copy them to your own computer now.
One thing that is curiously missing from the announcement is what alternative Blizzard has developed to its original Real ID forums concept since it was thrown out. StarCraft 2 has a centralized handle that is associated with your Battle.net login, and it is the same handle/avatar that's used for multiplayer games. Hopefully, they'll provide more details on issues like this as things start to lead up to the changeover.
The full blue post is after the break.