I appreciate your clear and upfront response. I shouldn’t have submitted this poll without giving substantial thought to the question and options first. I only wanted to get a very rough picture of how the main interests/hobbies/professions are distributed on HN, so I didn’t care much about rigor; but that probably negatively affects pollee morale. I’ll keep that in mind for the next time.
Explanatory text is good when it wouldn't bias the responses. Explicitly allowing multiple selects is good to be stated up front (see ColinWright's explanation elsewhere). Using an "Other" response is relevant when you don't intend to change the possible responses halfway through (and changing them effectively invalidates your results up until that point).
HN is the only place I've seen get regularly irritated by poorly-written polls; the Internet is filled with really bad ones, because survey design isn't taught unless your major actually needs them (i.e., user experience, social sciences, marketing and sales).