We need a hiring revulsion index
Perhaps you've heard of the "net promoter" index. This is where you ask customers if they would recommend a company's services to other people. You can be pretty sure you're doing something right if they're willing to pass you along to their friends, or so the logic goes. If you walk into a restaurant and they ask if you've been there before, and the answer is "I have, but they haven't", then you can guess one person is introducing the others to a favorite place.
What I want to see is the "hiring revulsion" index. It would be rather simple. All you do is grab a typical valley engineer type, and then say you have an awesome opening that's practically custom-made for them. Then when they ask where it is, tell them a company name and pay close attention to their response. If you get a sour look in response, chances are that things are not good for that company's reputation.
I'd like to see this kind of data graphed by time, company, and type of employee. You could see companies go off the deep end and watch others show up to take their place. You could also watch the type of employees being attracted change from experts to weenies. It might also be interesting to see if various biases start appearing.
Maybe using some drama could make it more interesting.
"You are ejected out of a 737 high over Silicon Valley when a structural defect causes the roof to rip off. You manage to stay conscious somehow and find you can change your trajectory a little. You're certainly going to go splat, but which company's headquarters do you aim for to hopefully make things a little more interesting for them? Alternatively, which company's headquarters do you avoid?"
Enough of these companies want you to stack rank people in biannual reviews. It's high time they got a taste of their own medicine.