Just a few minutes into the debate, Twitter traffic had already exceeded the tweets-per-minute earned by Mitt Romney's speech to the Republican National Convention (RNC). The Democratic National Convention drove more tweets than the RNC. Twitter later reported that the event generated a total of 10.3 million tweets related to the debate. The Democratic convention drove 9.5 millon tweets and the GOP one about 4 million, Twitter said.

Past political events that earned high Twitter traffic include Obama's State of the Union speeches and the Supreme Court's announced healthcare ruling earlier this year.

Twitter sentiment analysis indicates that Romney was earning more positive chatter than Obama online post-debate, according to a project from the University of Southern California's Annenberg Innovation and Signal Analysis and Interpretation Labs.

Updated Oct. 4 at 7:58 a.m.