A scientist (amateur?), viewing a newly discovered asteroid impact crater using Google Earth, impulsively decides to look for more. He quickly finds two candidates (Astroseti.org), but hours of additional work don't turn up any more.
It's a truism of the history of science that new instruments create a flurry of new discoveries. The new instrument in this case is not satellite imagery (old), or even Google Earth (though it's cool), it's the distributed worldmind. Lots of minds doing a vast amount of analysis.
After 9/11 I, among many others, proposed using a large collection of minds to process visual data from Afghanistan (obviously the security risks require some thought). I don't think that happened, but this story again shows us the potential of the new instrument.
Incidentally, the story of the early find and then nothing seems odd, but consider how many must have looked this way. The same idea probably occurred to tens of thousands of enthusiasts. The vast majority would look for a few hours then give up. If it takes 10,000 hours to find a crater, and the average search is one hour, then roughly 1 in 10,000 persons will make a discovery like this.