Bluehost, HostGator and HostMonster Go Down

If you host your website on Bluehost, HostMonster, HostGator or JustHost, your site is probably down or experiencing issues.
The three hosting brands are all divisions of Endurance International Group. The outage appears to be related to server maintenance at the Provo, Utah, data center.
According to the Bluehost and HostMonster Twitter accounts, that maintenance caused additional problems.
Unanticipated additional issues are occurring. We are continuing to update as more info comes in.— Bluehost (@bluehost) August 2, 2013
Although HostGator and Bluehost (two brands that used to operate under the same company) do not have a dedicated page setup for system status, HostGator has created a forum thread providing information on the system outage.
Bluehost and HostMonster report that their phones are overloaded with calls and that the company is doing everything it can to get its sites back online.
Update: Endurance International Group has started a blog for status updates.
It says in part:
During the morning of August 2, 2013, Endurance International Group’s data center in Provo, UT experienced unexpected issues that impacted customers of bluehost, HostGator, HostMonster and JustHost. Company websites and some phone services were affected as well.
Many of our customers’ sites are back online. Some customers may continue to experience intermittent access and slowness until services are fully restored. Customer should not experience any loss of data.
The resources of our entire company are focused on the recovery, including our executive team, which is leading these efforts from our command center in Burlington, MA. The team will issue updates at enduranceresponse.com every 30 minutes until all customer services are restored. Following the restoration of services, Endurance will conduct a thorough review of this incident.