It's about Pinch-to-Zoom patent

Apple just received 18 patents, one of those is Pinching-to-Zoom. Apple applied for the patent in 2006, while it just got it approved in 2010. Thus it took about 4 years.

Why did it take so long?

The process to acquire the patent is as follow:

Picture 1 Standard Patent Flow Chart

The flow chart above shows "Opposition Period", thus after the patent application accepted, the patent isn't immediately active. It needs to be opposed, then if it's successful, then it will become active.