Tuesday's debate a hit on social media

(AP)—Tuesday's presidential debate was a big hit on social media.

The 90-minute nationally televised exchange between President Barack Obama and Republican Mitt Romney generated 12.24 million comments on Twitter and Facebook according to Bluefin Labs, an analytics firm that studies social media's reaction to televised events.

The debate was the top political event of all time in social media and placed third among the top social media events of any kind, bested only by this year's Grammy Awards and MTV Video Music Awards. The first presidential debate, on Oct. 3, placed fifth.

The end of a tense exchange over immigration Tuesday night produced the biggest social media spike.

Women dominated the social media conversation about the debate. Some 54 percent of comments came from women, 46 percent from men.