When the Play store apk last updated, the folks at Android Police noticed some reference pointing towards a Google+ tie in with user reviews, and now it's live. We figured it was coming when we saw all the reviews on the web go anonymous, and now whenever you go to leave a comment and review for an app you're first told it's going to happen, then you're switched to your Google+ account to do the deed.
It's surely something that's going to cause user-backlash, but it should also lead to more helpful reviews now that you're tied an account to the review. It's also a good way to pump numbers up, so prepare for those news stories as well.
It's easy to check out yourself, head to Google Play and leave a review!