IMHO, a party that owns or invents a patent that it does not use and never intends to use in any real products and they only litigate with said patent makes it a true patent troll.
Leaving aside the desirability of software patents, the "real products" element is not a useful way to define who is a "troll." Economically, one of the functions of the patent system is that it allows specialization and division of labor. It allows you to take the results of R&D efforts and wrap it up into a property right that can be the subject of market transactions. ARM doesn't make CPUs; it sells IP that a wide variety of companies can incorporate into "real products." ARM's expertise is in CPU design. It's economically efficient to let it focus on that, instead of forcing it and every other R&D house to also master manufacturing, supply chain, etc.
(I'd also posit that this is a good thing for consumers because it is a force pushing back against vertical integration. In the long run, I think it'll turn out to be a bad thing for consumers that the market is moving from ARM supplying IP to dozens of manufacturers, to a handful of companies with like Apple and Samsung moving CPU design in-house within a vertically-integrated supply chain.)
ARM is a great example, thank you for pointing it out. Wasn't aware they didn't manufacture anything themselves but the benefit of their utility is pretty obvious.
No, words need to mean something. Patent troll is an organization that buys up patents just to enforce them while not actually using the patent itself within its own business model.
Microsoft is a patent gorilla, but it's not a troll.
I'd count anyone who wields trivial patents, or patents where previous work exixts and which should not have been granted in the first place, a patent troll too.
How do you feel about the patent for compact discs? James Russell invented the technology along with prototypes but never put it into production first-hand, electing instead to license the technology to other companies. There's no debating that companies profited handsomely from putting this technology into the consumer market. It built off prior work (LaserDisc) and the patent holder was a non-practicing entity (as someone else pointed out in this thread).
You're not a patent troll if you invented the patents (for a 1st-party OS).