This has been posted on a few websites but I don't think it has nearly the media attention it deserves.
Basically, Google messed up, badly. In a recent automatic Google Services update, Android Device Manager has had its Device Administrator permissions silently disabled - no warnings, no confirmation, AFAICT no effort by Google to alert users at all.
It's a simple fix if you know about it, just go and enable it again. But the fact it's been disabled like this means most people probably won't even be aware of it, and the lock/erase functions are therefore rendered useless.
So, if it's something you rely on, check it as the update is rolling out, if it's not happened yet it still might. I wonder if Google will do anything to regain trust in the feature that was positively received on release? Not much use in a feature like this if it randomly kills itself...
Oh and I understand some won't see this as too big a deal, especially if they don't use it, but it's bound to affect a fair few people, and speaks of general incompetence IMO.