Loading Hangouts from the Google+ web interface currently shows a vague, unhelpful error message and those using the Chrome extension for Hangouts will get messages claiming that the recipient "isn't on Hangouts at the moment". Hundreds of users are already flooding the stream with similar reports, suggesting that the outage is widespread.
"Things are taking longer than expected"
As of writing, the Apps Status Dashboard for Google services hasn't been updated to reflect the downtime, but we'll continue to update this post when we hear more, or when the chat service is back online.
|Error message on the Hangouts Chrome extension|
Update: As per a post from the YouTube's page, Google+ Hangouts is currently undergoing "Emergency Maintenance." The engineers are working on it now, and don't have an estimated time frame. We'll keep you in the loop.
Update: At 2:15 PM EDT, the Apps Status Dashboard is now reporting that Google Talk and Google+ Hangouts is restored for some users and should be up for all users "in the near future."