According to a press release from ABC Family, the finale generated almost 645,000 tweets, and at one point peaked at 32,000 PLL-related tweets per minute. Yes, per minute. That is insane.
According Deering Davis, the founder of TweetReach, a company that tracks the success of Twitter campaigns, the Pretty Little Liars finale was "one of the biggest hours of TV on Twitter" they've seen in their "several years" of tracking TV tweeting.
Furthermore, according to SocialGuide the finale was the #1 "most social" one hour episode on record, and Trendrr agrees that it was the #1 social media program of the night.
Basically, everyone in the world was online freaking out about all the twists and turns the finale took.
This success is a testament to the awesomeness of the show as well as the dedication and passion of its fans. Good job, Pretty Little Liars!