Judging from the table names in the article, it looks like they are maintaining virtually all of their data in a single database hosted on a machine that is connected to the Internet and accessible by anyone. This is a grave mistake in my opinion, regardless of whether they are using 3rd party software or not.

I forgot to say that blocking the same URL with Adblock achieves the same results. The feature works by letting websites post updates to the URL http://www.facebook.com/beacon/beacon.js.php. So if you block this URL with Adblock (or another extension), websites won't be able to update your profile.