...if they don't have interest/will to write something meaningful just for the sake of talking a little even for 15 posts...
I think you hit the nail on the head here with this observation. In the end, that's how some folk are going to do it, and we might have to just let them. If the majority continue to be interested, then that is excellent! More than anything, I want this community to be friendly, so I guess I'd feel bad if we had to brow beat newbies into posting more than they want to.
P.S. I know I'm terrible at expressing my thoughts and more often than not I have to clarify what I meant the post before, anyway I'm sorry for any possible misunderstanding.
I'm glad you commented, because we needed to be able to look at all sides fairly. As a result, I think I understand the issue better, and instead of feeling irritable about spam posting, I'll be able to be more encouraging next time it happens!