This is an interesting statistic for another reason aside from de-anonymization, particularly directory listing applications. A lot of web sites have url's to access the user's profile page by their username. For popular sites, it's always a rush to register "yourname" as a username so that you can get website.com/<yourname>. Inevitably, your name gets registered by some one else and you're stuck picking a nick name or appending a randomized letter set to it.
I've been pondering a useful way to have /<yourname>in a URL, so that everyone with that name can use the url containing it without collisions. Of course, I always end up with something like website.com/a3fx/<yourname>. Which is arbitrary, and ugly. However, with this stat it seems we have something close to a non colliding, pretty, meaningful addressing scheme. Ie: website.com/<dob>/<gender>/<zip>/<yourname>, sure it's a bit long but it provides assurance you're getting who you think your getting.
A problem with that is that people move, so zip codes change. You could fix that by substituting artificial, user-chosen groupings for zip codes if you used enough of them to have a similar distribution. Users could pick a grouping based on their interests, and you could even keep the geographical aspect of it by treating them as "neighborhoods". People who play the stock market could choose WallStreet, science fiction fans could choose Area51, wine aficionados could choose NapaValley, and so on.
I've been pondering a useful way to have /<yourname>in a URL, so that everyone with that name can use the url containing it without collisions. Of course, I always end up with something like website.com/a3fx/<yourname>. Which is arbitrary, and ugly. However, with this stat it seems we have something close to a non colliding, pretty, meaningful addressing scheme. Ie: website.com/<dob>/<gender>/<zip>/<yourname>, sure it's a bit long but it provides assurance you're getting who you think your getting.