And if I knew the answer, I wouldn't be a journalist.
Still, it's always interesting to get the reaction of developers who find themselves in that happy position.
Most recently, this happened to Appy Entertainment, and its FaceFighter app.
It's already been fairly successful since its June launch, and then it got listed as 'What's Hot' on the US and Canadian App Stores. Unsurprisingly, sales when through the roof.
The app is currently #9 in the US chart, although it peaked at #7 over the weekend. It's also #18 in Canada.
Neatly this excitement is recorded on Appy's blog, where they hope the uplift will continue until Apple's big announcement on 9th September.
They would be especially happy if this reveals an iPod touch S with camera, as FaceFighter lets you import photos onto the faces of the people you beat up.
Still, the folks at Appy also ponder why the app was chosen, as well as a laying out some solid rules about how to approach developing, marketing and supporting your app. It's well worth a read.
Don't forgot though that what comes up also comes down.
As developer Nimblebit pointed out; when its Moon Drop app stopped being featured, sales went back to their pre-featured level.
