Pennsylvania, New Jersey, and all America saw a campaign unlike any in history on Tuesday.

Not only did they vote. They also tweeted. They also Facebooked. And they used these social media to learn about where to vote, encourage others to vote, tell the world they voted - and complain about the battery of campaign ads. This was the day social media made politics a communal experience.

And as of 10:15 p.m., Election Day 2012 became the most-tweeted event in U.S. political history, with 20 million tweets.

Early on, it was a time for crazy stories and for celebrating the vote.

Crazy tales abounded, and Facebook and Twitter told them: an early tussle between the parties when GOP minority observers were reportedly turned away from some Philadelphia polling places, followed by a judge's order to let them in; confusion over voter ID laws; and the judge-ordered covering of an Obama mural at the Franklin Elementary polling place.

As never before, people tweeted photos of themselves waiting in line, of their polling places. A few, such as Fox News host Sean Hannity, tweeted or Instagrammed their completed ballot - an act which, as it turns out, is illegal in many states. Oops.

David Schuff, associate professor of management information systems at the Fox School of Business at Temple University, e-mailed that "one thing I am seeing on Twitter and Facebook is that people are making voting a viral, communal experience." Hash tags such as #ivoted exploded throughout Twitter; on Facebook and Twitter, many shared pictures of "I Voted" badges and stickers. Schuff saw people "interacting on social media while waiting in line to vote - I've seen some ask for last-minute advice on local candidates." WHYY's Elizabeth Fiedler tweeted that "these 'I Voted Today' stickers are everywhere."

Out of an average 13,000 tweets per minute early on Election Day, an average of 3,000 contained the words I voted.

Never before could voters reach, so quickly, such an astonishing cornucopia of information. Mary Ellen Balchunis, professor of political science at La Salle, liked former Rep. Joe Sestak's tweeting of polling place information, which she retweeted.

Kenneth Wisnefski of the Mount Laurel social-media consulting outfit Webimax notes that early on Tuesday, the Obama campaign brought out the #VoteObama hash tag as a last-minute organizing tool; in an election in which "4 out of 10 voters indicate their decision will be based on some of the activity heard on social media," the Obama campaign was "leveraging this to its maximum potential." The Romney forces soon launched their own focusing hash tags.

Stephanie Hatch, social media and e-mail marketing specialist at M.I.T., gave the Romney camp points on personalizing their Twitter tweets, always referring to Romney in first person, whereas Obama's, she says, were often "hijacked by his staffers," referring to Obama in the third person. She gave Obama points for being "proactive" and having better infographics.

As he has done since 2008, Obama used every available medium down to the wire. He went on the social site reddit - where he made a much-touted appearance in August, taking questions from reddit users - and urged readers to "go out there and cast your vote, whatever your political persuasion."

And then, of course, there was #stayinline, the hash tag that encouraged late voters in voting queues, especially in crucial states such as Florida, to stay in line and vote, as law allows them to do if they were in line at closing time. There were hoaxes, too, such as the tweet (premature, although it became true later) that NBC had declared Elizabeth Warren the winner against Scott Brown in the Massachusetts Senate race.

As never before, you could have the direct experience of watching the national vote. The New York Times offered an interactive "512 Paths to the White House," by which users could trace the combinations as the results rolled in. Facebook offered a voting app that let the user register when he or she voted, and a little "explosion" would go off in a large U.S. map. In real time, you could watch little explosions go off all over the country, giving an uncanny sense of where millions of Facebook users were voting.

That's a lot of information, a lot of media. And, ironically, social media probably encouraged the sense that it was all . . . too much.

"Social media has proven to be a valuable tool for this election," says Cara Rousseau, social media manager at Duke University, "allowing fact checking, interactions with candidates and analysis of sentiment in real-time results."

But a lot of people got tired of all the strong opinions. "An anti-social movement surfaced on Election Day, with people voicing complaints that they don't want to hear any more political commentary," Rousseau says. She did a Twitter search for the string off social media today and got hundreds of hits.