Thank you for linking those articles, that was very helpful.

That said, Google was lucky that there was a loophole in the patent definition. Imagine a world where Apple had actually obtained an airtight patent on a system that listens for single- or multi-touch gestures and switches between scrolling and pinch-to-zoom appropriately (which is essentially what the patent in question does). So, you'd be free to implement pinch-to-zoom as long as it doesn't infringe on that. Good luck.

(the point here being that, de facto, Apple would essentially have a patent on pinch-to-scroll. In real life [not in the proposed alternate universe] this is almost true -- there are loopholes, but you have to hire a patent lawyer to find and/or confirm them).