Microsoft formally announced the browser that has been kicking around in test versions for a year now. Internet Explorer 9 began rolling live last night. It’s faster and it supports the HTML5 standard, which can make for more dynamic web sites, capable of doing a lot more. CNET says that for a browser, it looks an awful lot like an operating system running a bunch of apps. That’s because those sites are able to do a lot more and resemble apps a lot more than the same old web sites we’ve been seeing for years. IE9 will not be compatible with PCs running Windows XP or earlier, which makes up for 40-50% of all machines.