At this point it's clear that genomes can't be anonymous, they can be linked back to an individual's identity. See: http://www.sciencemag.org/content/339/6117/321.abstract
The Personal Genome Project doesn't require people to share their identity publicly, but some participants would rather be public at the outset rather than have that information be pseudo-secret and a topic of gossip. It also opens the possibility of being directly contacted by someone who notices a health issue in your data.
-- Madeleine
As a scientist I'm going to be a total wet blanket and make a broader statement agreeing with this: it's unclear if actual effectiveness has a power law distribution, or if it's merely the claims of effectiveness that have that distribution. Extraordinary claims require extraordinary evidence -- the surprising part of the distribution is exactly the part we should be most suspicious of.
Of course, this is why we want GiveWell doing research into it. But I don't think they should assume this distribution is true.