The stats gathering systems for plugins and themes and core are currently offline for database maintenance. They will be back online as soon as possible.
In the meantime, the stats displayed for these items on org will not be collected and will show zeros for most or all items.
When the issues are fixed, the statistical data will take a day to gather and then redisplay for them.
The systems team is examining the problem at present and will have it back up and running as soon as is feasible.
UPDATE The switch maintenance is now complete.
UPDATE: Internap has announced a maintenance window starting Saturday May 16 at 2100 CDT to upgrade the software on the affected switches. They believe that the outage was caused by a software problem which is fixed in a more recent release. There should be no downtime as part of this maintenance.
Between 2000 and 2120 UTC today there were some intermittent connectivity issues which affected all of WordPress.org. In some cases this would have resulted in complete unreachability and in other cases it might have meant a 5XX error or higher than normal response time. The underlying cause appears to be a faulty network switch which has since been removed from production and we are working with the hosting provider to identify the exact issue before attempting to return the switch to production.
Plugins Trac is offline for a couple days while we get things resynced. The svn is working fine, but Trac takes a bit more resources and will be intermittent on both plugins and themes.
The plugins.svn.wordpress.org systems will be offline or in read-only mode while maintenance is being performed, starting at 2000 UTC. This is expected to last no more than 2 hours.
There was an intermittent switch failure which affected some WordPress.org services between 0200 and 0353 UTC. The WordPress.org website and API were mostly unaffected.
There was a switch failure which affected some WordPress.org services between 2300 and 2357 UTC. The WordPress.org website and API were mostly unaffected.
The support forums on WordPress.org will be undergoing an upgrade and will be in a read-only state on September 1 between 14:00 and 20:00 UTC. More information is available on this make/meta post.
From August 31, 20:30 UTC through September 01, 00:30 UTC (four hours total), we will have a maintenance window for plugins SVN. During this time, plugin authors will not be able to commit to the SVN repository.
Edit: Maintenance has been completed, and the plugins SVN repository is available for commit once again.
On August 27, 2015 between 05:00 and 11:00 UTC, we will be performing network maintenance, which could result in a temporary outage. Keep an eye on this post (and this site) for any updates.
07:15 UTC. Maintenance complete.
WordPress.org experienced downtime due to a load balancer failure. The network is now up and the incident is being investigated.
18:17 UTC. A denial of service attack is currently being mitigated.
At 19:44 UTC the attack was fully mitigated and all services were restored.