We have recently finished integrating the Platform to the website so it is now running in sort of a "public beta test" mode. You might experience slowdowns or timeouts for short periods, but otherwise it is expected to be working correctly.
If you've previously selected (in your browser) to stay logged in, you'll remain logged in and can still do your regular activities until your cache expires - or you choose to log out.
Once you're logged out (either through cache expiration or logging out manually), you'll need to reset your password in order to log in again. This is also necessary to fully activate your Platform account (technical note: we don't store passwords, so we couldn't migrate that).
We have migrated all active users, so you don't have to create a new user. Your track record (ie. your posts) is also saved.
(Of course we have backed up everything and can revert should we need it, though it is expected to remain a theoretic option.)