Privacy

Tests of the site's design

Now and then we show visitors one of two versions of part of a page, to see which works better. So that you keep seeing the same version, your browser keeps a random id in a cookie called xp_id for a year, with xp_v (30 minutes) and xp_s (a year), which note the versions you've seen. They hold nothing about you, and we don't use your IP address for this. We count which version you saw and whether you clicked or signed up, in our own statistics, not Google's.

You can opt out. You'll then always see the usual version, and nothing is counted. Your choice is kept in a cookie called xp_optout for a year, on this browser.