No truer words have been written about the Internet and your reputation than the following:

Again, what you post on the internet can have broad implications on your life and career. What others write about you can also have profound implications.

This is certainly true–as many people are now finding out. The entire industry of reputation management services exists because this is demonstrably true.
http://www.slaw.ca/2009/09/10/managing-your-online-reputation/