https://docs.google.com/spreadsheets/d/1bIYwuz3bhRWPYazVamMD...
All data is anonymous. You don't even need to be logged in to edit.
What do people think of this?
I'm not a stats person, but it would seem to suffer from both an extremely small potential sample (those who read your post), a self-selection bias (those who gain an advantage by participating, e.g., the aggrevieved), and an outright unsual candidate sample pool (Hacker News).
Perhaps try something like Google Consumer Surveys, and ask a one-two question like: (1) are you currently working for a pre-IPO startup and (2) are your options underwater. Or similar.
The best you'll be able to do is a site like glassdoor, with all the sample bias that implies. But even with glassdoor, I've told a recruiter to go away because their company pays poorly according to glassdoor. The recruiter then whined about glassdoor, but since he didn't provide me with salary numbers, what does he expect?
I've also pondered building a site similar to glassdoor to confidentially discuss outcomes, but the best you'll ever be able to do is anecdata.
[1] http://www.bothsidesofthetable.com/2015/10/18/venture-outloo...