In my opinion, it's more like checking if a key exists in a hash, if you know that there's a 99% chance that key hashes to one of 50 possible values.<p>There are only a few incriminating apps, such as Zoosk (I use "incriminating" in the lightest sense possible of course), and you can just visit the pages for those apps individually.<p>I've been a pretty harsh critic of Facebook regarding privacy lately (see my previous comments) but I don't think this specific instance is a privacy fail, unless you are arguing that it should be possible to completely prevent people from knowing what apps you use.  And that's fine, but app install visibility is one of Facebook's less flagrant privacy violations when you look at the whole picture.