We discussed that question here:

https://www.duolingo.com/comment/15562777

I said that if you put Esperanto on your resume, the response at an interview (if you get one) will certainly be "what the heck is that?".

A few people replied that they got their current jobs thanks to having Esperanto on their resume.

For my part, I have it listed at the top of my foreign languages. People have asked about it, or skipped over it. People are always very interested - at least to my face, I suppose.

My thought is that it doesn't belong under hobbies. If you don't speak it well enough to call it a language, it probably doesn't belong on the resume at all. I think it helps if you have more than one language.