Traces of oil.

The most immediate reaction came from those monitoring oil stock prices.

Transocean Ltd. today reported a fire onboard its semisubmersible drilling rig Deepwater Horizon. The incident occurred April 20, 2010 at approximately 10:00 p.m. central time in the United States Gulf of Mexico. The rig was located approximately 41 miles offshore Louisiana on Mississippi Canyon block 252.

Subsequently, on April 21, NOAA published their first incident report (now considerably enhanced).

The first news stories, particularly the local New Orleans news stories, focused on the loss of 11 lives in the explosion and ensuing fire.

By April 23, the destruction of the Deepwater Horizon oil rig had received global attention.

And then the story began to change. On Saturday, April 24, the U. S. Coast Guard, which had been searching for the 11 missing oil rig workers without success, acknowledged an oil leak at the rig site. The Coast Guard estimated the leak at 1000 barrels a day.

Twitter and other social media were already covering the event — the #oilspill hashtag was in use early — but these were, at the time, mostly echoing information that had already appeared in more conventional media. From this point forward, coverage of the Deepwater Horizon incident by mainstream media and by social and alternative media diverged.

Because of the isolated location of the Deepwater Horizon site, there were few visuals for broadcast media to run and rotate. In the beginning, aside from footage of the oil rig fire recorded by the Coast Guard, the Gulf area maps distributed by NOAA were, by default, the most oft used and repeated images in the mainstream news.

Stymied by this lack of live action, corporate broadcast media turned to their stable of talking heads: interviews and opinion pieces that mentioned the environment and President Obama and British Petroleum, but revealed little about the cause and extent of the Deepwater Horizon oil spill.

Conventional print media sources – some, at least – manipulated NOAA and other government data in creative ways, turning one sort of graphic into another sort, based on the same data. None significantly questioned that data – in particular the widely quoted estimates of the amount of oil released and the area of the Gulf covered by that oil – until a leaked government memo was turned over to the Mobile Press-Register, and, later, when a revised set of Gulf oil estimates appeared on SkyTruth.

In their unrelenting scrutiny of corporate press releases, contrived media events, and, most of the all, the money, social and alternative media have been consistently more insightful than a barrage of conventionally packaged and repetitive news stories sandwiched between Lost and Glee.

On CNN, for instance, there have been some informative comparisons of Deepwater Horizon and the Exxon Valdez – but based on little more than what was already available through Google and Wikipedia, and on much less than you could find and learn about the more relevant example of IXTOC 1. There was a widely distributed, live-action video of a pelican with oil on its wings, and a full day’s worth of dead-turtles-on-a-beach stories — without much consequence. There was an interview or two with General Russel L. Honoré — with obligatory references to Katrina. And there were lots and lots of commercials.

Similarly, the New Orleans Times-Picayune’s reporting on the Deepwater Horizon oil spill has remained dedicated and professional, but can do little to match either the stamina or the information flowing from innumerable Twitter lists such this one, compiled by a faraway correspondent for OnEarth magazine and including, among others, local @HumidCity updates.

And now, as the Deepwater Horizon story slides off the lede and breaking news agenda of conventional media — failing to provide live-action images of oil lapping onshore — social and alternative media continue to bring the heat.

Yes, probably the best information has come from a combination of mainstream and alternative/social media sources. But, if you had to choose only one source of information about the Deepwater Horizon incident — something like Twitter, or something like CNN — which would you choose?

Another good question: How can an organization with the limited budget and staff of a SkyTruth – or a Wikileaks – accomplish what conventional news media, with all their resources, can’t?