How does JobBoostio choose the right job boards?
Almost all connected job boards are "Generic" JobBoards. That means that all sorts of jobs are welcome. Also, visitors search on these job boards by entering search criteria and/or filters.
E.g. they're looking for "engineer" jobs in the "Amsterdam" region. Now the job board will show the visitor all available relevant job boards. Therefore this job board also addresses the right active searching target audience.
See this Talent.com example (click image to enlarge);