Basically it's what programs offer when they don't want to comp you totally. It's like "have X stays/nights in N days and we'll upgrade you to the status requested".

There have been several offer like where they granted Gold for 4 stays in 90 days (in which case it would be good to have 4 1-night non consecutive stays and then book the remainder where you'll have the gold benefits), and I read recently about a fast-track to diamond for 7 stays in 90 days.