Some folks are just searching the internet for any kind of help with their own issues. They land up here, join and ask for information to help resolve their problem and that's it. Maybe just not 'forum folks' or just feel they have nothing to contribute.
At least they always find sensible and accurate advice.

Sad in a way when people feel they have nothing to contribute, we all have experiences, ideas, values and opinions worth sharing.

Joe, you're right there are those who join and pop in from time to time solely to take.
They never update or mention that the forum helped, then pop up again for more help some time later. Not much to do about that.