Why? Because NetBeans went through a massive migration process during the past week, during which many obsolete projects have been removed from the site and a lot of restructuring of everything has taken place. The good news is that the whole site is now under the control of the NetBeans team, rather than a third party. The so-so news is that several things still need to be tweaked to get everything working correctly now that the migration itself has come to an end. For example, currently, it's not possible to log into the Plugin Portal yet, though that should change within the next few hours.
New passwords and other info has been sent around to mailing lists as well as individual subscribers.
The complete story with all its ramifications can be found here: http://wiki.netbeans.org/NewNBOrg
If you encounter any problems, please report them to:
There'll be several loose ends in the next few days, so please be patient as things are being ironed out. And, remember, from now onwards, use firstname.lastname@example.org (instead of email@example.com).