Yes, that is possible with a bit of know how. You could do that with scripting or with a program; similar to the leeching program that ripped from places like Warez-BB a couple of years ago.
But there's something you're missing.
If you rip off those posts, you are taking content posted by others that is not yours.
If you want your site to be a success - it's going to take a lot of hard work - and even then nothing's guaranteed. But ripping off others to try and fluff up your post content and numbers; that's just asking to fail.