Though Instagram has seen some big changes this year — from shooting video to displaying ads — the service appears to be more popular than ever. On stage at an event this morning, Instagram CEO Kevin Systrom announced that more than half of the service's 150 million users are active on the app each day. Though Instagram shied away from giving updated statistics on total users, it also revealed recently that its busiest day ever was on Thanksgiving this year, marking the second year in a row that Thanksgiving set a new daily record.