UPDATE 6/25/2015 1:15PM EST: All sites should be operational again. We're continuing to look into the issue to see the exact cause.
UPDATE 6/25/2015 1:01PM EST: Many PHP sites are working again, but real estate sites are still having issues. We are continuing to work on the issue and will update you when we have more information.
ORIGINAL 6/25/2015 12:25PM EST: A recent update to Cpanel (the control panel for our web sites) caused an issue with PHP web sites. We are working on it now and will update you when we have more information.