"I give you the ability to do this because I trust you" - Metafilter Guidelines

<i>Due to a few opportunistic members that ignored guidelines in the past, there is a one-week waiting period after signup, before you are allowed to post a new question to Ask MetaFilter or a new post to MetaFilter. You can post comments to MetaFilter and MetaTalk, and answers to Ask MetaFilter right away though.</i><p>Trust works best in small communities. A few bad apples can ruin the whole experience as the community grows. Within no time the community degrades if it is just based on trust. A saner way to do this will be to trust people to do the right thing, but verify that they are not doing anything malicious.

Metafilter's $5 sign-up fee is incredibly smart. I imagine it brings in a decent amount of income and it really keeps the community top notch.