[trickypr]

I think a lot of your examples are flawed. Google didn’t build the initial version of YouTube, they bought it.

A lot of Apple’s apps predate the App Store. The apps that came later had limited use until Apple spent a lot of time refining them. Think Apple Maps.

Microsoft released Word for Mac a year before they released Windows 1.0, so Windows was “down the stack” for them.

[dosinga]

eh, maybe. Sure Google bought Youtube, but the whole making it social came later. Apple spending a lot of time refining them is exactly the point. They did go up in the stack (given that they started out as home computer builder quite a bit). Word first came out for MS DOS, so definitely going up in the stack.