Google OAuth is the system that enables you do log into a service (like, say, Etsy or Trello) with your Google or Gmail account. Many Twitter users reported the API associated with Google OAuth wasn't working at about 9:20 a.m. ET on Tuesday, locking them out of various services.
The outage follows a possibly unrelated Gmail disruption that occurred on Monday, according to Google's Apps Dashboard, which monitors service disruptions and outages across Google services. Read more...