Brilliant idea. I've thought about doing something like this in the past (thanks to milliondollarhomepage, which inspired the idea). Here is another idea that is very similar: (Search "mrwong.de + myhouse" in google, sorry I can't post links yet.) I think the thing to consider when doing something like this is what's in it for the customer? If I came to your site why would I want to buy a word from your site? Is it just because other people are doing it? If so, you should play that up more as a marketing tactic. Is it for advertising? Seems thats the quickest and easiest way to get this kind of thing to work. You may have a hard time "selling words" to people who may or may not care less about owning one. Maybe target this to niche experts who could benefit from buying a word from you relevant to their niche keyword and use it as a link back to their site. Start some viral buzz around your site to show your prospects that people do indeed visit the site and will potentially click on their purchased word (link back to site). Does that make sense?
It's a cool idea and I like the website, but I'm not so sure that you're going to find people that really want to own all those words (since they have to pay for them)...
Sorry, variations of this have been going around since like 2006, you've just added a tiny twist. They usually take up to much time and dont make enough money, why would I come to you when g, yahoo and msn has the market for "buying words" I say scape this and do soming that's less of a gimick sorry, I just like telling it like it is, that's all. Best Daniel