You give us a keyword and we combine it with our carefully selected list of nouns, verbs, and adjectives. Then we search the results for unregistered .com domain names.
Checking hundreds of domains for availability takes a while, so we use multiple servers in parallel to speed things up. Currently, we have six domain lookup servers spread across five different datacenters.
Our domain name generator is written primarily in Node.JS, with a bit of PHP used for domain availability checking. Node acts as the primary webserver, domain generator, and also handles load balancing across our pool of lookup servers. We use servers from AN Hosting and Linode.
Here at Impossibility, we have a team of over 40 talented programmers and designers... Well, actually, it's just me. If you happen to be a Photoshop user, you should totally check out my Photoshop text effects.
2011-11-07 - New word lists: Five and six letter nouns, verbs, and adjectives! Note: these new lists are experimental and occassionally rude ;) The original "four letters or less" word lists have not changed.
2011-11-19 - Slightly decreased font size to allow more domains to fit on the page. Added Google +1 button. Click it! ;)