If this sounds sketchy as fuck... it is. But it works, and you can basically tell the recruiter what you want to do and when that op shows up in their network he or she will advise you and help you get the deal.
If this sounds sketchy as fuck... it is. But it works, and you can basically tell the recruiter what you want to do and when that op shows up in their network he or she will advise you and help you get the deal.
In forming a good relationship between their hiring partner and interviewees - they know who is likely to be a "fit" and who will not be. This is no different to HR screening CVs based on fit, the only difference is that recruiters of take a personal vested interest in the success. Every hire nets them commission. Every good hire strengthens their network, every bad hire weakens their network. If they are truly a network-based recruiter, they want every hire to be amazing.
Yes, there will be weaknesses in this system. Yes, it leads a reduced hiring pool (if you opt-in to this style of hiring) and black-box hiring. The upshot is that as an interviewer and interviewee you save yourself time and find yourself a job that makes you happy, you only need find yourself the right recruiter.
If you're an engineer there's a list of requirements that would convince you to switch jobs whether it be for working in a certain industry, with certain proven founders, your comp., certain tech, title a company can offer, remote/flexiblity, benefits, etc. When I meet a candidate and they tell me that list and a few months down the line I come across a job that matches well it's a win-win for both me, the company, and the candidate.
tl;dr recruiting can be a relationship-based game with many moving parts. At a certain point, with a complete and up-to-date dataset, you can provide tons of value for everyone as an information arbitrator.