Hours after news broke of the April 20 Deepwater Horizon explosion, the first of the “boycott BP!” pleas could be found on Twitter, on random weekend eco-warrior blogs and here and there on Facebook. Now, the movement has snowballed into a social media cause célèbre, replete with Twitter flash protests, celebrity backing, damning homemade documentaries and satirical updates from an official-seeming company mouthpiece, the fastest growing account on Twitter. Where have we seen this all before? Yep, BP is facing its “Tehran moment,” with the anger of millions threatening to do irreparable damage. Can BP clean up the mess before it’s too late?

Let’s take a look at the multi-front reputation-wrecking assault BP faces at the moment from various social media channels.

Facebook: As of this morning, the primary (there are 293 of them) Boycott BP Facebook page had a following of greater than 172,000, a gain of 54,000 since CNN reported its existence two days ago. The primary page has become a massive community Wiki tallying the number of dead turtles and pelicans. It’s also a place for cathartic venting. One of the more reserved charges, reads:

“Disgusting death mongers! BP’s CEOs should be forced to get out there and clean up the oil with their bare hands!! :<”

Twitter: #BP has been a trending topic on Twitter for weeks now. But the tone is growing nastier, shifting from OMG!-the-spill-is-out-of-control tweets to plans for street-level activism such as flash protests at BP filling stations around the U.S. Here’s an indication of what BP is facing:

This chart above tallying “BP protest” tweets shows a type of “snowball effect” growing in recent days, the result of a recent spate of news stories that detail the Boycott BP campaigns occurring on Twitter, on Facebook and on blogs. The news articles are then re-Tweeted, re-posted to Facebook status updates and published on still more blogs, creating an amplification effect that will be hard to counter from a PR standpoint. Journalists can now dip into this story whenever they want, using fresh numbers and fresh outrage to put a new slant on an old story.

YouTube: Over 6,000 videos have been posted to YouTube in the last month detailing the extent of the environmental damage by the Deepwater spill, reaching millions of viewers. The videos run the gamut from crude satire to the conspiratorial to community outrage.

Any hope for BP? BP’s PR crisis management task force should note: there is precedent here. Last June, a global community of outraged voices took to the Internet to demand change in the form of the infamous #iranelection protests. For two weeks, protesters, aided by a globe-spanning social media support group, defied President Mahmoud Ahmadinejad’s armed goons, circumvented government censors and communications blackouts, to voice their opposition to a dodgy election. Then, one day, the momentum behind the Iranian protest lost steam and fell out of the public consciousness, replaced by an even bigger story.

What event could have been so big as to distract us from the potential toppling of a despotic regime? It was the death of Michael Jackson, considered at the time the most tweeted single news event ever. This is the nature of online protests: they come out of nowhere and have the potential to captivate and sway the masses, only to fade from view just as quickly when the next big thing comes along. BP’s crack PR team understands this full well, but that’s little comfort. The King of Pop is dead, and so too are a lot of sea turtles and pelicans.