This information will only affect those following the bleeding edge of bbPress and WordPress development.
bbPress now has implemented in it's trunk both the new "phpass" hashing for passwords and the new "authcookie" cookie methods which are slated for release in WordPress 2.5
This means that if you are integrating WordPress and bbPress then you can now test out the latest versions of each.
If you have any feedback or problems with integration then post here or on the bbDev mailing list.