Re: Integration with MU 1.5.1
WPMU is adding some extra information to the end of wordpress’ username cookie content.
For example, the old cookie content is simply “admin,” while the new cookie is “admin” + a number like “%7C1211540101%7Cb954a41e23200ea6951bdeb405dc5237.”
Perhaps this is some kind of hash? I know WPMU 1.5.1 added a salt key to the wp-config.php file, so maybe that has something to do with it.