A customer wanted to know if is possible for an application to edit the user's Start page.
No, there is no interface for editing the user's Start page or even knowing what is on it. The Start page is the user's personal space and applications should not be messing with it.
Imagine if it were possible. Every application would edit the Start page to put themselves at the front!
It turns out that the customer wanted their application to make some changes to the user's Start page when it was installed. Specifically, they wanted to hunt down tiles belonging to their competitors and delete them, then insert a tile for the newly-installed program in exactly the spot the competitor's tile used to be.
In other words, somebody was looking to get a really nice bonus.