Tweckle (twek’ul) vt. to abuse a speaker only to Twitter followers in the audience while he/she is speaking.

Conference speakers beware: Twecklers are watching.

They’re out for blood.

And you may be their next victim.

Once upon a time, conference goers could do little more than passively fork their cheesecake when a snooze-inducing keynote speaker took the podium. No longer. The microblogging service Twitter is changing a staple of academic life from a one-way presentation into a real-time conversation. Flub a talk badly enough and you now risk mobilizing a scrum of digital-spitball-slinging snark-masters. This is from a higher-education conference in Milwaukee:

• we need a tshirt, “I survived the keynote disaster of 09”

The Twitter “back channel” can be a powerful tool to quickly knit a gathering of strangers into an online community, a place where attendees at meetings broadcast bits of sessions, share extra information such as links, and arrange social events. But the same technology can also enable a “virtual lynching.” That’s the phrase one twitster used to describe what happened at last month’s HighEdWeb Association conference, an event that has gone down in social-media history as perhaps the most brutal abuse of the back channel yet.

The setting was a midday keynote speech before some 400 college professionals in Milwaukee. The presenter was David Galper of the now-defunct online music service for college students, Ruckus Network. The Twitter reaction as he spoke included the T-shirt suggestion, and continued:

• it’s awesome in the “I don’t want to turn away from the accident because I might see a severed head” way
• Too bad they took my utensils away w/ my plate. I could have jammed the butter knife into my temple.

Perfect conditions propelled this Twitter torrent: a speaker who delivered what was apparently a technically flawed and topically dated talk to a crowd of Web experts who expected better. They reacted by flaying him with more than 500 tweets in one hour. The onslaught grew so large that it went viral—live. The conference became one of the most popular topics on Twitter, meaning strangers with no connection to the meeting gaped at Mr. Galper’s humiliation when they logged onto their home pages. One consultant who coaches academics on public speaking now uses the disaster as a what-to-avoid case study.

And it all started at 11:59 a.m. with one measly, harmless, innocent tweet, a dig at Mr. Galper’s hard-to-read PowerPoint slide: hella drop shadow.

“You just start down the slippery-slope mentality,” says Michael P. Fienen, Web marketing manager for Pittsburg State University, in Kansas, who was ferociously egged on by the zap-Galper twitmob—@fienen! @fienen! @fienen!—and now admits he may have gone too far. “Twitter makes it very slippery and very steep.”

The Great Galper Fiasco blitzed the blogosphere, but other examples of less dramatic Twitter rudeness and goofing now surface regularly.

Take the recent National Association of Science Writers meeting in Texas, where the trigger was a tweet about a Purdue University climate researcher’s black-on-black Nehru jacket. One listener followed with a question about who was cuter, Kevin R. Gurney, the speaker, or Virgil Griffith, a California Institute of Technology graduate student who gained fame for developing an online tool to catch self-interested parties polishing their own Wikipedia entries. The Twitter back-channel conversation degenerated from discussing carbon emissions to evaluating “studmuffins.”

• I’d have to say Virgil. But I wouldn’t kick either of them out of bed, so to speak.
• Gurney. Virgil’s prac underage!
• 10 yrs. ago, Karen produced calendars with male scientists in sexy poses (none w/less than speedo on) ran out of talent.

The twitiquette continues to evolve, as people experiment with different strategies to handle the back channel.

One conference tried to squelch it by publishing social-media “courtesy” guidelines in the program: Don’t post during talks. Don’t “oversimplify” speakers’ remarks. Don’t make personal comments.

Some fight back by publicly calling out twecklers. That’s the approach Jonathan P. Bacon took in response to impatient audience members who grumbled about being forced to listen to “boring old men receiving an award” during a ceremony that preceded Lawrence Lessig’s keynote at this month’s Educause conference.

“It’s a little bit like talking while somebody else is talking,” says Mr. Bacon, director of the educational technology center at Johnson County Community College, in Kansas. “People need to be polite about the tweets and the chatter that go on in the back channel. I think people forget that what they say goes to a larger audience.”

Others suggest embracing the back channel by monitoring it during presentations. Some conferences actually broadcast the Twitter feed on a screen as the speaker talks, which has two advantages. Speakers can use it to interact with the audience and take questions. And the audience is less likely to step out of line if the feed is running in the room for all to see rather than hidden in the snarky glow of a private laptop screen.

Purdue University has produced a technology that makes tracking the feed even easier. Called Need4Feed, it displays the most popular tweets at conferences. Steven W. Tally, a strategic marketing consultant at the university, points out that people are accustomed to commenting about articles they read online. Now they want to comment in real time about speakers, too.

“We’re going to have to get used to the fact that you’re not speaking to a group now—you’re really leading a conversation,” Mr. Tally says. “And if you’re not listening to the other people who are participating in that conversation, it’s not going to have a good outcome for you.”

You may even end up on a T-shirt.

By 1:34 p.m. on the day of Mr. Galper’s twit-slaughter, someone had already visited the Web site CafePress, mocked up a shirt called “Twitter Disaster,” and shared it with the conference. Its message: “I Survived The #heweb09 Keynote.”