At the start of Election Day, Facebook pointed out that users will gradually see a prompt at the top of their page (and as a notification on their mobile app) to declare that they’ve voted and motivate friends to do the same. However, many users noticed that the prompt seemed to be timed to follow moments of inactivity, presumably following a user’s journey to the polls.

Earlier today, many users noticed that the prompt (as seen below) was not on their page this morning, but popped up after they were away from the computer for a while:

This “I’m a Voter,” button has proven to be pretty popular. In the 2010 election, the prompt drove an extra 340,000 users to the polls, according to a University of California, San Diego study.

A Facebook spokesperson said that there’s no hocus pocus going on, noting that notifications were “rolling out throughout the day.”

Readers: When did you see the “I’m a Voter,” prompt on Facebook?