Could you please tell me how one could make use of good ranks on programming challenges web site (coderbyte, hackerrank, CodeEval) to enhance one's resume/CV? When does something like this matter?
Yes, they matter, in two cases:
- When your rank on such websites is high enough to prove dedication and skill.
- When you've won or placed well in an important competition.
If you find yourself in any (or both) of the two situations above, then yes, you should add everything as relevant experience on your CV. It will surely help with looking good when applying to any job, especially those that require quick and efficient problem solving.
The reason I've mentioned those two cases is because admission to such websites is usually free. Just being a member of a website dedicated to algorithmic challenges doesn't mean you're actually doing anything there.