The next level of this money-making venture is to actively search out popular domains that are coming up for auction and transform them into something useful: you can just put a bunch of ads on the page if you want.
The key is to buy a domain that everybody is already going to.This traffic may come from search engines, or backlinks to a site that once existed at the URL.
Google has a service for this called Pagerank (named after founder Larry Page), which lists websites according to their relevance within a certain topic. It uses complex algorithms and other things that fly way over my head, but it essentially ranks sites based by the number and quality of links that are directed to that website.
Anyways, the money-making part: there are several plugins which will scan the auctions of domain-registry websites like GoDaddy.com and automatically sort through the domains based on their PageRank (which is publicly available). These plugins are incredibly useful because they put all this information right in front of you with just a click, as seen in the picture to my left:
Doing a quick search, the best one I've found is at FFPlugins.com
It's clean, professional, and really straightforward, which is way more than I can say about the other plugins I tried. Using their GoDaddy Auctions Plugin, I bid for a couple of sites right before they expired, and they are now making money for me through adsense. It's kinda strange how much traffic you can get with a high PageRank, but I'm not complaining.
With the two domains I've bought, I've made more money in a week than I make in a week at this website (Shelby's Shells, unfortunately, does not have a high PageRank). Check it out if you're serious about this money-making stuff.
Once again, the link is here if you're interested