Google has tried a few (mostly unsuccessful) strategies to get Android device makers updating their software in a timely fashion. Remember the short-lived Android Update Alliance? However, it might be trying something different: embarrassing those vendors into doing something. Bloomberg tipsters claim that Google has created lists that rank Android manufacturers based on the timeliness of their updates. They're private right now, but the company is considering making them public to shame vendors that drag their heels -- it's hoping those brands too sluggish to make the lists will strive to do better.
Other work has been going on behind the scenes, too. Google has been asking carriers to shorten their notoriously long update testing cycles (Sprint has confirmed it, but Verizon reportedly has too), and it's even pressing carriers to skip tests entirely for security updates. Google isn't commenting on the leak.
It's far from guaranteed that the lists will work, assuming they're ever made public. The Update Alliance fizzled out as commercial realities (the cost of maintaining phones, and the desire to sell you a new phone instead) took over. What's to say that a list with no direct consequences will do any better? However, there isn't as much pressure to update as there was in the past. Google Play Services delivers many updates without having to go through makers or carriers, and numerous official apps get updates through the Play Store. This is more about going the last mile to both improve security and reduce the chances that hardware creators leave you high and dry.