> Do you ever feel guilty being a lurker?

No, not when it comes to the decision not to have a blog, or a facebook page, or a twitter account, or a non-throwaway HN login.

Others may disagree, but I see profound narcissism in the popularity of these (plat)forms of expression, which are mostly about signalling.

If you feel guilty about "not contributing" then contribute in some meaningful way. Contribute features, support, and/or bug fixes to open-source projects (or start one from scratch if you've an unreachable itch.) Teach people how to do stuff. And have enough self-confidence not to need to "share" literal or metaphorical selfies.