This is month-old news by now but I hadn’t gotten around to writing about it yet and it’s fairly important. Google Places now lets business listing owners reply to reviews on their listing directly within the listing.
This is important because previously there was no such functionality. As a business owner, you had to contact the reviewer directly in order to thank him. In more difficult situations, such as when you received a negative review that was not factually accurate, you would have to contact the reviewer, work out a solution, and beg him to rescind or correct the review. This was a nearly impossible task, especially because many reviews are effectively anonymous.
With the ability to reply directly within the business listing, all visitors to your listing can see that you at least try to resolve issues and recognize customer concerns, as well as appreciate positive comments regarding your business.
I assume that Google probably notifies a reviewer if a business owner has replied to his review, which is an added bonus because it keeps the conversation going and strengthens the business-to-customer relationship. If Google doesn’t send a notification, it certainly should.
It’s also probable that Google will be paying attention to business owner replies, possibly extracting semantic value, and using this in the future for other purposes. Minor ranking factor for Google Places listings? Maybe. Some other analysis for future products/features/algorithm tweaks? Probably.