Understanding semantic zoom

As per the UX guidelines for the Windows Store app, the content flows horizontally and the user will, either by mouse or by touch, scroll the content from left to right or right to left (in some languages). But imagine a scenario where you have content that features a long list of data, such as in the case of an address book or maybe a list of different news articles, where scrolling to navigate the content becomes cumbersome for the user. In the case of an address book app where the contacts are organized alphabetically, the user has to scroll all the way to find a contact whose name starts with the letter z; that is, at the end of list, while the user could zoom out to the view level that only lists the letters and find a specific contact that falls under that letter.

The same goes for a catalog or a news app that organizes items/articles by category; instead of long scrolling to reach the desired content, which falls under a category that happens to be at the...