Twitter

What began as a cable television quip turned into an online atomic bomb last night when Democratic strategist Hilary Rosen criticized Ann Romney for having "never worked a day in her life."

The comment, made on CNN's Anderson Cooper 360 shortly after 10 p.m. Eastern Time, earned a life of its own on Twitter, sparking a war of words that propelled both Romney and Rosen into the stratosphere of 140-character mentions.

In the two hours following Rosen's remarks, the number of times Twitter users mentioned her name skyrocketed from less than 10 mentions per minute to more than 170, according to data compiled by Twitter. At 1 a.m. Eastern, a mere three hours after Ann Romney sent her very first tweet, mentions of the presidential candidate's wife shot to 240 per minute.

The fervor continued on Thursday. At 11 a.m., when Mrs. Romney went on Fox News to fire back at Rosen over her comments, the Twitterverse went nuts, firing off more than 260 tweets per minute about Ann Romney. That's more than one and a half times as many mentions as Twitter superstar Justin Bieber, who has close to 20 million followers, as Buzzfeed pointed out.

In the 13 hours after Rosen first bashed Romney's stay-at-home mom status, three top Obama campaign advisors, the chairwoman of the Democratic National Committee, the chairman of the Republican National Committee and the First Lady had all tweeted about the incident.

Each of those tweets sparked its own mini-storm online, with Obama campaign strategist David Axelrod's tweet getting close to 500 re-tweets.

"The shift from a 24-hour news cycle to a 140-character one has dramatically reshaped the rapid response game," said Adam Sharp, Twitter's senior manager of government, news and social innovation.  "The whole action-reaction-response cycle is compressed to mere minutes, and Twitter users have a front row seat to a back-and-forth that used to be witnessed only by the 'boys on the bus.'"

But while the speed and scope of the Romney-Rosen Twitter showdown was big, it was not unprecedented. In fact, it pales in comparison to 140-character madness that was created when Rick Santorum announced he was dropping out of the GOP presidential race on Tuesday.

As the press assembled for what was supposed to be a 2 p.m. E.T. press conference, Santorum's Twitter mentions were hovering around five to 10 per minute. But by the time the candidate took the stage at about 2:29, people were tweeting his name at the explosive rate of about 2,307 mentions per minute.

By 2:36, when Santorum gave the official word that he was dropping out, the Twitterverse was in a full frenzy, pumping out more than 2,550 tweets per minute about the now-former presidential candidate, proving that when news breaks, the Twittersphere takes note. Many, many notes.