To locate a Favimon, you use the keyboard to type a web address in the box at the top of the page. If the site is in the surprisingly robust database, it appears for a mouse-controlled turn-based battle. Each Favimon has stats for health, attack, defense and speed, as well as four appropriate actions used to dominate your foe. Starting you quest with the original Favimon site icon, defeating other websites adds them to your team and then become available to use in future battles. There's no real goal other than collection, but man, there are thousands to collect.
Favimon relies almost entirely on the novelty of its central gimmick. That's okay though since the gimmick is quite novel indeed. Racking up all those Favimons in your Favidex is just incredibly compelling. Certainly some icons look better in large form than others (and, in a not-updated browser, they'll look more blurry than pixelated), and the attacks do get more generic the further you get from the top domain names. However, this is easy to forgive the second you set up a Google vs. Facebook grudge-match, or use Paypal to zap Wikipedia with a "Transaction Fee" attack. Favimon isn't all that deep, but as a charming time waster it's super effective!