Part of the value that LinkedIn adds is that there is some degree of authenticity to the resumes.
There are some API standards for background checks between businesses and agencies, so that could be a good place to start. You could offer authenticated profiles, where people can't lie on their resume about where they worked.
Of course, LI could just implement this if you became too competitive to them.
It's not perfect but it makes it possible to spot lies. For example if you manage your company's profile on LinkedIn you can see when a new person says they've started working for you, and you can click a "they don't really work here" button. Of course people can still claim to work for "Y C0mbinator", but then on their profile it won't click through to the same company as listed on other people's profiles.
It also let's you make better judgements on likelihood they're lying. It's not impossible to create an authentic-looking fake profile, but generally speaking if you see someone claiming to work for X company and connected to lots of employees from X company it's a safe bet that they worked there.
I wish I knew. My last background check was through HireRight, and the only reason I know they have automated systems set up with different employers and agencies is because one of the systems screwed up and needed manual verification.
Did that at one point. Lost the JSON file in a hard drive death though :/ The day prior to the crash I had wrote a note to put it in a git repo and then forgot. Otherwise it's a pretty nice way to manage a resume.
