The data presented here shows that tangled packages/classes are quite common. This suggests that the belief that tangling is a *negative* property, is in odds with reality (Of course, this is not a scientific study).
In the Mythbusting post I said that tangles of packages are benign. I based this claim on the fact that many successful libraries contain such tangles. In particular, I said that 20 out of 23 libraries that are bundled with the Spring framework, do contain tangles. Here are the actual graphs of five libraries/tools which you might be acquainted with.
These images were produced by Structure101.
Update 1: Added the preface (as per vinod's suggestion)