We've written plenty of stories since January about how promotions via the FreeAppADay website have boosted game sales.

This is another of those stories - this time for ustwo's MouthOff app - except that the inclusion of download and revenue charts makes it very clear what's going on.

Or as ustwo's mills puts it: "40 pound average a day prior to FreeAppADay, 175,573 free downloads in six days, 270 a day in sales after, plus picked up on staff favourite in US".