Apple is increasingly playing defense against lawsuits from Samsung and Motorola that seek to take iPhones and iPads off the shelves and out of stores. Apple is trying to do the same to their competitors, of course, but there's a subtle difference -- Samsung and Motorola are suing Apple over FRAND (Fair, Reasonable, And Non-Discriminatory) patents and are apparently seeking licensing that's anything but fair and reasonable, and may in fact be discriminatory.
FRAND patents are typically typically pledged as part of a standard, which makes them essential to a technology, the organizations that govern those standards require them to be equitably licensed back to everyone. That's the whole point of having standards. If you want your invention to become a standard, you let it be used as a standard.