Defamation in the Internet Age

Having done some reading this week on the several fake quotes attributed to Rush Limbaugh, it seriously concerns me that it seems so easy to damage someone's reputation. If you aren't familiar with the quotes or how they were evidently fabricated in order to brand Limbaugh a racist, you can find an analysis on About.com.
Personally, I don't really care all that much about Limbaugh himself, I find him to be way too obnoxious. What I do care about is the idea that someone with a little determination and a Wikipedia account could fabricate a quote which could eventually become accepted fact. If you think that Limbaugh's case is isolated, maybe you don't remember this famous hoax. While not as mean-spirited, the made-up quote by Shane Fitzgerald would likely have been attributed to Maurice Jarre permanently had Fitzgerald himself not intervened.
Here's how the fake-quote cycle happens:

1. An anonymous individual posts fake quote on Wikipedia.
2. Another individual picks up the quote for use in an article or book and doesn't mention Wikipedia as a source.
3. The quote, which has since been removed due to the lack of a documented source, reappears with the aforementioned article or book as its source. It is now legitimate.
   

Of course this will never happen again because all writers and reporters are thorough and ethical, right? The simple fact is that for every good writer, there is a lazy, incompetent one out there who will use shortcuts like Wikipedia.
Now, more than ever, you just can't believe what you hear.