Fewer tweets during second debate

Users were sending 109,560 tweets per minute at the peak moment during Tuesday's debate, when the candidates discussed immigration and Romney slipped on a questioner's name.

The economy was the most discussed topic, followed by taxes, foreign policy, energy and immigration.

The fastest-rising buzzword for the debate was "binder," after Romney said he chose from "binders full of women" for senior staff appointments when he was governor of Massachusetts. "Pension" and "Jeremy" (a college student who asked a question) were also popular terms.