Here's a (non Metro) example:
Say you have a Word document and you want to find the word "Oz". With the document open inside Word, you'd use Edit/Find. That's find in page, and you shouldn't use the Search charm to do that in a Metro app. You'd typically make that functionality avaiable
from the AppBar.
If, on the other hand, you want to find every document on your hard disk that contains the string "Oz" in its filename. You'd do that in Explorer. It's a multi-file search, and that's the kind of functionality you provide via the Search charm.
If, on the other hand, you have say a ListView and you want to filter its contents, you'd probably do that directly on-canvas via combo boxes in the header.
HTH
Rebecca M. Riordan
