About three weeks ago, Apple’s Developer Center went down because of a hacker intruding into the Web site. Apple explained that little or no information was compromised because of secure encryption. Slowly but surely, Apple's Developer Center has been coming back online with improved security since the incident.

Apple has sent out an e-mail to developers with another update on the situation with the Developer Center:

Quote Originally Posted by Apple
We are pleased to let you know that all our developer program services are now online. Your patience during this time was sincerely appreciated.

We understand that the downtime was significant and apologize for any issues it may have caused in your app development. To help offset this disruption, we are extending the membership of all developer teams by one month. If you need any further assistance, please contact us.
Apple's Developer Center is now up again and fully functional for developers; every feature is now back online and displays a green square rather than an orange triangle by the features in the System Status Indicator.

In addition, Apple is extending all developer memberships for an additional month to make up for the three-week period that the Developer Center could not be used by anyone. The extra time should give developers a chance to get back on track with their work without feeling cheated out of their subscription.

Sources: Apple via MacRumors