If you don't want to be spoiled, read no further.
There were actually two big reveals on the episode, titled "unmAsked." First, viewers learned that former misfit turned popular girl Mona Vanderwaal (and supposed fellow A victim) was in fact the person behind the vowel. Well, one of them, anyway.
Because the other big reveal in the episode was that there's more than one person working as A, a "Team A," and the person pulling Mona's strings -- another member of Team A -- visited her in the episode's final moments after she'd been committed to a mental institution for severe personality disorder.
Just because she's in an institution doesn't mean Mona's story is over. In fact, actress Janel Parrish, who plays Mona, announced on Tuesday that she's been upgraded to series regular for "Liars'" third season.
While the fact that A's identity was revealed (or partially revealed) wasn't a surprise -- producers had teased the development well in advance -- the actual details were unexpected. And to judge by the fans' reaction, hotly contested.
It's possible "Liars" fan Twitter Waiting for #March19 (the date of the finale episode) had its expectations set a wee bit too high. The reaction? "The producers of #PLL are pretty little liars themselves cuz they didnt give us a real answer for who's A."
Another fan, Lisa Hiser tweeted, "I'm sorry #PLL, but was definitely not satisfied with that reveal. Too predictable...and the real "A" wasn't really revealed."
Laura Lithgow of the Dominican Republic saw the season finale as a breakup of sorts. She wrote, "Now that I know who A is..is not the same:( I will miss Pretty Little Liars </3."
British fan Devon-louise Oakley shared a similar sentiment when she wrote, "Knowing who A is has taken the fun out of pretty little liars for me but that was shocking."
ABC Family shouldn't go into crisis mode just yet, however. There were still plenty of fans who reacted with sentiments similar to Jordana Silva: "OMG pretty little liars was amazing."
-- Patrick Kevin Day
Photo: Ashley Benson is one of the stars of "Pretty Little Liars." Credit: Eric McCandless / ABC Family