Could your provide a specific example of how to use a binary search to find a salary? A binary search is dependent on boundaries. I don't see how it could be used effectively to find the boundary for a specific employer. Also, the flow chart shown in the article has no similarities to a binary search. The article describes the more reasonable approach: using networking to find out what a domain in an area pays.

You can't do it for a single employer because you only get one test per employer. You do the search across employers, in an area/domain. That gives you a rough idea of the prospect.

Yes, networking and insider information is much better than any of this.