By a rough estimate, the library at Windows Marketplace now tops 21,000 apps -- nearly twice the amount we reported near the end of May. While some platforms might be envious of this recent flurry, many of the titles are merely variants of single applications -- uploaded by the hundreds -- that flood the Marketplace, while forcing other qualified coders from the spotlight. It's no cakewalk for customers either, who must wade through the deluge when shopping. In attempt to bring sanity to its store, the company is now restricting developers to (a rather lenient) 20 certifications per day and is pulling the worst offenders from the shelves. Not looking to burn bridges, however, Microsoft has promised to teach methods of creating custom, localized apps without the need for submitting dozens of versions. Supporting in-app purchasing would be a fine start, but we'll leave that for Mr. Ballmer to flesh out. Not like he's busy with anything else these days.