Funny you bring up Facebook, because what I you really need to solve this type of problem is something like Facesmash. (sidenote: I don't know if that was actually a real thing or just something in The Social Network.)
You want /r/roastme for coworkers-- but private. Somewhere that you can rank former coworkers and they can rank you-- But the biggest selling point needs to be that this dossier is only ever available to you. NEVER to potential employers, coworkers, etc.
There are some interesting problems-- like delaying/masking the changing in your ELO such that it can't be tied to people you know have ranked you, otherwise you'll get an obvious bias because people don't want to risk a burnt bridge.
But I think if people are honest about their salaries on such a site, you can give them a reasonable idea of if they're being underpaid.
You want /r/roastme for coworkers-- but private. Somewhere that you can rank former coworkers and they can rank you-- But the biggest selling point needs to be that this dossier is only ever available to you. NEVER to potential employers, coworkers, etc.
There are some interesting problems-- like delaying/masking the changing in your ELO such that it can't be tied to people you know have ranked you, otherwise you'll get an obvious bias because people don't want to risk a burnt bridge.
But I think if people are honest about their salaries on such a site, you can give them a reasonable idea of if they're being underpaid.