Is that really the case? I find quite a few users seem to check replies to their comments -- so eg: answering a question usually isn't a waste of time. It would be if the person asking a question doesn't have 1k karma (see other comments for riff on this topic). Just struck me that this is rather bad -- while hn isn't (probably nor should be) a "stack exchange" type site, there's always someone asking on a story "what is this X that everyone here seem to know". Where X is anything for traditional MVC to data normalization etc[1]. I'm sure we all have some gaping holes in our knowledge of computer science and history -- having such questions answered seems to me to be a good way to maintain a sense of community.

[1] For example, not realizing that RC4 is now hopelessly broken, and asking for a couple of recent references.