If you ask me, Apple's finally realized that the Publishing industry, even when it comes to publishing software one way or another, is a serious business where you have to separate the wheat from the chaff.
As much as I hate to admit it, being a writer who's only had one short story published years ago, publishing is a matter of looking through thousands of manuscripts to find one that really catches your eye. Up to now, Apple has let pretty much anything go into the app store, but I'll tell you something, most of those apps, especially the 'rude noise' type or the 'digital business card' type rarely last beyond the first few days.
However, this has given them a database of app styles and types that now lets them look at download statistics to see what people are really willing to buy, if even for a short time. Because they're publishing digitally, they don't have the cost of producing a physical object that eventually may need to be merely tossed/recycled, but they do have the cost of maintaining the library and honestly, keeping a file of something that only 'sold' for two or three days and now languishes in ignoble obscurity is not worth the disk space it occupies. What with the announcement of the iPad, Apple has likely realized that if Apple wants to be more than 'just another app store,' they need to ensure that the apps they approve are quality products, whether they're games, tools, shops or merely entertainment.
What with the many different types of apps they already have, they now need to categorize, analyze and effectively edit the listings to present the cream of the crop. They need to do as the managing editor of any publishing house must do and try to ensure that what they publish is what their customers really want. Just as I wouldn't want to go down to the bookstore and pay $10 for something created by just any grade-school child, I don't want to go into the App Store and crawl through a pile of garbage to find that true gem of an app--the one that could let me use the iPad the way I want to use the device.
Publishing is a difficult business, no matter if it's books, movies, television or software. We've all read horrendous reviews of products in every medium and we wonder how those products ever made it to the market at all. Well, Apple appears to be trying to make sure its market has products that truly do what they say they will.