Phuctor is an online app with a simple enough concept – gather as many PGP keys as possible and check to see if there are different users using the same RSA modulo. Given the probabilities of such a collision (especially with keys greater than 1024 bit) are remote such a collision could indicate that a flawed implementation of PGP was used to generate your key or the matching keys were generated on hardware with a broken CS-PRNG.
If you’re curious then head on down to the Phuctor website. Obviously this tool will only be useful if a large number of users submit samples. For this reason I wonder whether one of the team should contact one of the keyservers and request a dump of their database. They are generally happy enough to do this for research purposes
UPDATE: I made a 4+ GB keydump from the Internet SKS keyservers available to Stanislav a few days ago. Hopefully this significantly increases their sample size.