There's a story that I think I read in The Passionate Programmer, although I could be wrong about the source... anyway, the author was trying to recruit a team in India. He had a thousand basically identical resumes. How do you triage that? So he added Ruby as a requirement. It wasn't really a requirement, but it self-selected the resumes for those who take an active interest in programming, not a passive career approach. That got them down to a few dozen resumes to dig through.

I haven't had to hire for myself, but I've done plenty of technical interviewing over the years, and worked with countless programmers. Most just aren't the kind of material I would want to hire. The ones I would want to hire, even if they haven't used Clojure, would be excited about the idea and at least conversant in the advantages (and disadvantages) of functional languages relative to OO languages.

So it's making the job harder, but also easier.