along the lines of 'those who stand and wait, also serve', there are lurkers (you know who you are!) who rarely post.

they are registered... and are welcome.

there have been times, when we(the long time poster) have been accused of running a closed club- partly because some of the long time posters know each other, not just in cyber world, but in the real world. Even those of us to don't know each other in the real world, have developed long term relationships based on a long time knowledge of each other (in the cyber world).

Deleting a member because they don't post as 'often' as You (or I) think they should would make it closed club. It would send a message: only regulars welcome, posting once or twice, and lurking not permitted!--a message, i don't endorse!