I recently passed a milestone: I've walked over 10 million steps while playing the game Pikmin Bloom. I didn't notice at the time; the app didn't pop up an achievement badge for 10 million like it did for previous round numbers.
You might think the app designers, by not handing me another achievement, missed an opportunity to keep me enthused about the app. Then again, Adrian Hon recently blogged about how game designers shouldn't over-rely on achievement badges to figure out how to "gamify" everything, e.g., how to gamify walking around. So I guess they're doing something right.
