100 consective day visits, > 400 votes, 0 questions, 0 answers.
Smells either like a sockpuppet, or a consciencous observer. No offense if it's the latter.
I actually would think that this is encouraged. It sounds like somebody who, rather than asking repeats of existing questions, is actively exploring the site/community.
I greatly prefer this than the multitude of easily-googleable questions that I see on SF, especially by those with very low reps. (It's like trolling without the bad behavior!)
Caveat: Even the easily-googleable question scenario isn't that much of a problem...
He's young. He's a programmer. Probably just all excited about the wealth of knowledge to be found on SF. :)
The only thing that bothers my about this kind of behaviour is whether or not he can fairly judge a good or bad question or answer, considering it's not his field, and might be voting inappropriately.