As long as I've been here, I have seen very few of these. There seems to be an influx of people making double and triple posts whose purpose is to tell people to post.
Example:
no one is posting :( plz post i go crazy for vehicles
plz post
This is directed at those of you who make these kinds of posts.If no one has posted yet, it's because they don't have anything to say. Asking people to post has no benefit whatsoever. All it does is make other members annoyed and provides an annoying bump. If you're going to bump, say bump, but at least wait until the topic gets close to being pushed to the second page.
tl;dr -- "Please post" posts: Don't make them.