StackOverflow and Hacker News both seem to actively discourage casual participation. I am the sort of person who doesn't like to speak unless I have something

StackOverflow and Hacker News both seem to actively discourage casual participation. I am the sort of person who doesn't like to speak unless I have something new to add, so I don't post comments or answer questions often. However, I'm quite happy to use my time and energy to tend the garden and pull weeds, and plant something new when I happen to have a really great seed. HN and SO both tell me they don't want me there -- fine, their sites, their rules. But I do feel this encourages a high noise to signal ratio, eventually clogging the site and making it less useful.