Garmin's first step tracker, the vivofit, came out 9-10 months back, and with it came "badges". There are badges for "steps", but currently, the last one is for 2 million steps. Maybe people have passed this if they's been using a vivofit from early on.
Badges get less common as you get more, so how about if after 2 million, there is a 5 million, 10 million, etc?