Over the course of its long, storied existence, Apple's been number one in many things, in many ways, from customer satisfaction to profit share to mainstreaming technology itself. Being the world's number one target for patent trolls, however, is likely a distinction they wish they didn't hold. John Paczkowski on AllThingsD:
According to PatentFreedom, which tracks some 710 intellectual-property profiteers, Apple has been on the receiving end of 171-patent troll lawsuits in the past five years: 27 in 2009, 34 in 2010, 42 in 2011, 44 in 2012, and 24 in 2013 — which isn't even over yet.
One hundred and seventy-one suits. That's more than any other company in tech, including Google, Amazon, Microsoft and Hewlett-Packard.
That doesn't include Apple's more legitimate suits and countersuits from the likes of Samsung and Motorola, not even the FRAND ones. These are pure non-practicing entities looking for a payoff. It's likely not all the suits are valid, and while Apple has significant money in the bank to fight back, it's a waste of that money, and of Apple's time.
Even so, it's far, far worse for small developers who can't afford to defend themselves. See the rest of Paczkowski's article for more, and for Tim Cook's past comments on litigation.