Thomas Edison was a patent troll

My last few posts have been anti-patent troll, so I thought I should try to balance them out with a different perspective. Most of us agree that patent trolls are bad. Many of us agree that the words patent trolls and non-practicing entities are equivalent. However, non-practicing entities can include research universities, which we don't necessarily consider "trolls". Or do we? Is there such a thing as a good, legitimate patent troll?

In a previous blog post, Opposition to patent reform, that I wrote in response to "An Examination of the Economics of the U.S. Patent System", I said:

Individuals, small businesses, and universities, can develop ideas into inventions. Although they don't have the ability to manufacture their inventions, surely they should be able to apply for patents and receive royalties from manufacturers. Right?

Along similar lines, there is an article in Slate that calls Thomas Edison a "patent troll" and says that patent licensing by "trolls" is nothing new in American history. Adam Mossoff writes:

Edison would have been wiser to continue to embrace market specialization—inventing in his lab and selling or licensing his patents to others to manufacture and sell his innovative products. It was doing this that brought him his fame and fortune as a young innovator at Menlo Park, and ironically it would have brought him notoriety today as a "patent troll."

There is an article at IPWatchdog that that refers to Edison and many modern non-practicing entities as licensing firms but not patent trolls. Unfortunately it does not define what the difference with a patent troll is.

The best clarification I can come up with is from the Electronic Frontier Foundation on trollingeffects.org where they state:

A patent troll is often more formally referred to as a patent assertion entity (PAE)—an entity that exists solely to assert patents against other actors, i.e., use patents to threaten litigation and extract settlements. A non-practicing entity (NPE), broadly defined, is an entity that owns patents but does not create any products based on them.

I prefer the phrase patent assertion entity (PAE) because it would appear to exclude universities and other non-practicing entities that do not solely exist for the purpose of patent assertion.