Today is Ed Balls Day, an annual tradition in which Twitter users gather to commemorate a memorable social media encounter. It’s been 11 years since the infamous social media blunder.

It’s a day to commemorate a 2011 gaffe that has made social media users laugh for more than a decade—and no one is more amused than Ed Balls himself.

But why is today Ed Balls Day, and what happened on April 28?

Former MP Ed Balls mistakenly tweeted “Ed Balls” on April 28, 2011, leaving many to believe he was trying to search for his own name on Twitter but accidentally posted it instead.

Users on Twitter reacted positively to the mishap, declaring April 28 “Ed Balls Day.”

Balls chose to leave the tweet up rather than delete it, and it is still accessible eleven years later. The tweet has over 111,000 likes and has been retweeted over 118,000 times as of this writing.

Balls is well aware of the joke, and has been tweeting “Ed Balls” on this day for the last several years.

On the tenth anniversary of the incident, he tweeted: “Ed Balls #10LongYears” last year.