StackOverflow and its family of sites (http://stackoverflow.com/) have in place a mechanism to detect duplicate posts based on the title and, to a lesser extent, the content of a post as a user is writing it. This is one of several things to help prevent post duplication and help users find answers to their questions. I think a similar mechanism on here would go a long way to not only help weed out the trolls, but also help people find information without having a million posts of things like "I'm only eating 700 calories, why am I not losing weight?!", or other such topics that are covered in other posts and even the stickies.

A little late on this, but I searched before I posted :) I totally agree with this. I was going to post that the site should require someone to search before they can post. The database we use at work does this. You can't automatically create a new profile. It first takes you to a search query, then the next page will give you a create option.