I had something like this installed on my site, but it didn't work out too well. Users would bitch and moan about having to make one post before being allowed to download anything. I've received tons of emails about it and decided to remove the post barrier until I can decide a proper way.
One thing I've learned is you can't force participation.
I could lock my site down, ban people for not posting or contributing, but that isn't something I want to do.
in the last 5 days, my site has received on average 33.2 posts per day and for the first 22 days of july, it was on average 84.18 posts per day.
I'm sure if my site was ran similar to how coders was it would get a lot more posts, but I'm not interested in doing that. Since this is your site Trailmyx, you can do whatever you want, run it how you want

that's whats good about running a site, you're in control.
I don't script asm uch as I'd like, but I'll definitely try to stay active here