NBC’s Chuck Todd might have summed up Thursday’s events best with this tweet:

Books about this campaign will have chapters simply titled: “January 19th”

— Chuck Todd (@chucktodd) January 19, 2012

Mitt Romney faced mounting pressure to release his tax returns as reports surfaced Wednesday night he might have assets in bank accounts in the Cayman Islands.

The Des Moines Register declared that Rick Santorum actually got more votes than Romney in the Iowa caucuses.

Rick Perry announced he would suspend his campaign in a morning news conference.

Newt Gingrich’s second wife, Marianne, said in interviews with ABC and The Washington Post that the former speaker had asked her for an open marriage.

And Gingrich exploded at moderator John King within the first few minutes of the CNN debate that night.

And yet, through it all, Ron Paul maintained his lead on the @MentionMachine leaderboard this week. We measured tweets from Wednesday at 7 p.m. through Friday at 4 p.m.

The candidates, with the exception of Santorum, saw significant surges in the volume of tweets about them, but perennial top-mention-getter Paul still had more mentions than any of the other candidates.

Paul had a relatively drama-free week compared to his remaining rivals, and recent tracking polls peg him to finish third in the South Carolina primary. But his grasp on the top spot in the @MentionMachine, as in practically every other online poll ever conducted, is firm.

Read more on PostPolitics.com

Mitt Romney’s big week in @MentionMachine

Follow @MentionMachine on Twitter