There's no doubt the Redmond team is spending a hefty amount of time enhancing its search engine at any chance it gets. Adding to the Linked tweaks we'd previously seen, Microsoft's now making Bing more social -- at least in the US of A. The most recent changes bring a Metro-driven interface to the homepage, which boasts that Microsoft "three column design" we laid eyes on earlier this month. Naturally, the revamp will open the doors to improved search results, but this, of