Rough Type helpfully summarizes Amazon’s claim:
The patent, as Amazon describes it, covers “a hybrid machine/human computing arrangement which advantageously involves humans to assist a computer to solve particular tasks, allowing the computer to solve the tasks more efficiently.” It specifies several applications of such a system, including speech recognition, text classification, image recognition, image comparison, speech comparison, transcription of speech, and comparison of music samples. Amazon also notes that “those skilled in the art will recognize that the invention is not limited to the embodiments described.”
Here’s the full claim. Considering that “the Turk” originated in 1770, I think there may be a case for prior art. But seriously, this is the same scheme used by Project Gutenberg to correct scanned books. Not that prior art carries much weight with the Patent Office lately. In fact it seems you can get a patent for just about anything. Case in point: this patent for a method of swinging on a swing.
The deeper problem is with patenting software at all; see Richard Stallman on software patents.