I'm generally inclined to agree with others here that this is far from a change of heart at Getty, but if it catches on it does give them the option of shutting the image down when they think the use is commercial. Personally I think this looks like a death knell for the extortion letters -- after all under this scheme they now have complete control over whether an image is displayed. It's going to be hard to send a demand letter for that!
Instead I think they'll take a broad and inconsistent approach, sending letters telling people "hey if you want our wonderful, glorious image back on your site, just send us $400". I think they're going to find that approach less fruitful than they expect but we'll have to wait and see.
One of the personal ironies in this is I'm also a pretty decent photographer. I pulled my stock from iStockphoto when Getty acquired them (moved to Dreamstime). I've since had two invitations to list with Getty (both before I got my very own demand letter for my business site). Both times I'd told them that hell would have to freeze over twice before I'd let criminals represent my work.
Lastly this should be on my other thread, but I'll keep it brief: I had a lawyer look at my approach of billing Getty for responding to their demand letters. His only advice was that I bill for time spent researching and preparing the letter, rather than for the letter itself. Other than that his comment was "a judge would probably find these costs quite reasonable". So if they continue with their extortions, don't forget to bill for every minute you spend reading these forums! In my case they went quiet just after I sent them registered mail indicating that they now owe me more than they claim I owe them!