Twitter users around the world complained they were unable to post comments on the site on Monday evening, provoking a wave of angry and humorous complaints published - where else? - on Twitter.
For long-term users the outage brought back memories of the service's early days, when server glitches brought up a cartoon of a beluga whale being lifted into the air by a flock of net-wielding birds.
Instead of that iconic "fail whale" image, this time around disappointed posters got a graphic-free error message saying: "Twitter is overcapacity. Please wait a few minutes then try again."
Some said they had problems trying to post new messages.
Others said they encountered it when trying to retweet posts....