3
i completely understand why he might want to do that.
Some sites have large files available for download such as mp3, video clips, programs, game hacks, etc. When your site is relatively popular thousands of people come in, download ALL your files and destroy your bandwidth. A post requirement is a way to regulate bandwidth, encourage participation, and turn away people that in my community are referred to as "leechers"... because they won't bother to make a few posts to get access.
Smartdownloads from
http://smartfactory.ca/ has this feature built in. For other modules, I think you would have to enter some code into the module's header.
...
I hate Mortal Kombat