- It's not particularly outlandish or constrained - at least compared to the earlier PoCs with CAPTCHAs or chess boards.
- It collects information without breaking immersion. This is done by alternating between "real" and "probe" asteroids. The real ones are always visible and are targeted at the spaceship; if you don't take them down, the game ends. The "probe" asteroids, which may or may not be visible to the user depending on browsing history, seem as if they are headed for the spaceship, too - but if not intercepted, they miss it by a whisker.
- It is remarkably high-bandwidth. Although the PoC tests only a handful of sites, it's possible to test hundreds of URLs in parallel by generating a very high number of "probe" asteroids at once. A typical user visits only a relatively small and uniformly distributed number of websites from any sufficiently large data set, so only a tiny fraction of probes would be visible on the screen. In fact, the testing could be easily rate-limited based on how frantic user's mouse movements have been in the past second or so.
- It's pretty reliable due to the built-in "corrective mechanisms" for poor players.
May 04, 2013