The site has a pretty comprehensive database of both U.S. and international airports, and it's up to users to supply data on the available internet connectivity (wireless or wired), its quality and cost.
You can navigate the airports via a drop-down menu or you can use the search function. A tiny Google map is also included for every airport in the database. It's all very simple but also pretty usable, although the huge CNET ad is diverting the users' attention from the main content.
As far as available data goes, well, the site is new, so there is very little information at this point. Airports in cities like Vienna, Zagreb or Barcelona yield no results, and even in the USA I had to click a couple of times until I got any info; actually, the only city I've managed to find info on was New York. However, CNET will probably push it a little, and I don't doubt it will be swarming with information in a couple of months. Nice idea, well done, CNET.