Actually, it's not terribly difficult to pull the Internet equivalent of escaping to a deserted island. All it takes is time and tenacity.
A good place to start is with a Google search of your name to see if anything unsavory pops up. Remember that Google isn’t your enemy; it's just the messenger. If you want to remove some embarrassing things you've said in a forum - or bad things that have been said about you somewhere - you need to get it removed from the original source.
Find an email address or phone number for the website in question and talk to a person who has the authority to grant your takedown request. Most websites have a Contact Us link at the bottom of their home pages.
If you can't find contact information, a "Who Is" Google search will tell you who registered the site. Type "whois www.name-of-site.com" in quotes.