If you’re interested in the beginnings of the project, we are glad to share them! The whoishiring.io website started around August 2015 with the intention to display Hacker News’ "Who is hiring" thread on the map and allow for sorting and filtering the humongous list of job offers.
After getting it up and running, we put in on Hacker News as a "Show HN" thread (if you're not familiar with the concept you can check what "Show HN" thread is here). To our surprise, the post got a lot of attention along with a plenty of comments and feedback. The response was so motivating that he decided to dedicate more time to the project and see how can it be improved.
Along with the consistent addition of sources, whoishiring.io strives to make a developer's job hunt a less painful experience. Perhaps the hiring process is not that big of a deal as it is currently portrayed. Maybe it’s all about the visibility?