Mike Masnick made a nice graphic: direct link
And he wrote: "Now, here's the crazy part: this is just lawsuits. I thought about showing licensing deals in this chart as well, but that would have killed my whole weekend (in fact, just as I was finishing up this post, I saw that Microsoft has just licensed 74 smartphone patents from Acacia). And then I thought about including companies like Intellectual Ventures which apparently are sitting on a bunch of other smartphone patents but haven't yet sued over them. However, I'd already wasted hours that could have been spent doing other, less brain-damaging work, and decided to leave it like this and move on.
Anyway, I'd say this does a damn good job demonstrating the concept of a patent thicket. It also explains how such thickets are hindering innovation. Anyone who wants to get into the smartphone business knows that they're facing lawsuits from a large number of the companies listed on the graphic. "
