UPDATE: And it's back! However, it appears follower counts have (most likely temporarily) been reset to zero.
Twitter updated its Status blog with the following message: "Twitter is currently down for some users. We are aware of the problem and working on it."
Twitter's Fail Whale is making a splash on Twitter.com today, which can only mean one thing: Twitter is down.
DownForEveryoneOrJustMe.com confirms that the site is down.
At the time of this post, Twitter's outage seems to have lasted around 15 minutes. There's no mention of any service disruptions on Twitter's Status blog.
Twitter isn't the only one having troubles: Skype was also down today.