I think it's possible this might work. I also think getting it to work, if it does work, will require either impossible luck or a lot of effort to build a useful database up front in order to attract users and build a community.
The way I see it, if I go to the site for the first time and paste in a recruiter email and there's nothing in the database, the odds I come back go down significantly. If against odds I come back a few hours/days/weeks, later and have the same experience, I will probably decide the site is useless.
In some ways, the site is a marketplace where people are buying information [at least with their time]. If the database does not produce relevant results, then in terms of a market their are no sellers. An empty database is useless no matter how many queries it gets and pretty much nobody does data entry for fun.
In the short term, there needs to be a market maker - someone who makes sure that sellers can sell and buyers can buy...and here it is the buyers buying that needs help and the form of a market maker is someone who goes out and fills the database with useful information and that's probably the website owner and if that doesn't sound worthwhile then the appeal of doing so for random people on the internet may well be similar...even if data entry gets gamified via awarding points/badges when the data gets returned in a query.
The challenge in the problem Frecruiter tries to solve is social more than technical and the social success will probably require more than a call for data entry volunteers.
Good luck.