Twitter announced early Thursday morning that Wednesday night’s presidential debate in Denver was the most tweeted-about event in U.S. politics. There were over 10 million tweets during the debate, according to the company.

“The topic of tonight’s presidential debate was domestic policy, and citizens all over came to Twitter to share their comments and follow millions of real-time responses from pundits, campaigns, and fellow voters,” said Adam Sharp, Head of Government, News, & Social Innovation at Twitter.

The moments in the debate that generated the most discussion on Twitter were when moderator Jim Lehrer said, “Let’s not,” when Mitt Romney requested a topic, when President Obama said, “I had 5 seconds,” when Lehrer gave a time limit, and the general discussion about Medicare and vouchers.

Twitter shares the following chart looking at the “pulse of the conversation” throughout the debate:

“As the evening proceeded, several other trends emerged on Twitter,” says Sharp. “While @BarackObama and @MittRomney sparred over details of their respective economic plans, viewers at home attempted to keep up with the statistics and promises from each of them. Several Twitter accounts were dedicated to fact-checking throughout the evening, and fact-checking Tweets saw a great number of of retweets.”

There were over a quarter million tweets mentioning Big Bird, after Romney made comments about Big Bird and PBS funding, Twitter says, pointing to a few parody accounts that were set up based on the Big Bird comment.

With all of this tweeting happening in realtime, I wonder how useful Google’s realtime search with the Twitter firehose might have been.