At school, Tim Quirk's friend had an English cousin who sent over new records from the motherland. Now he's paying the favor forward as head of Magnifier, a blog informing Google Music Beta members about new, interesting bands with free, exclusive tracks. One click adds the exclusive content to your Music Beta library. Google is calling Magnifier a "music discovery" site, making a big deal that only artists the editorial team thinks are "pretty great" will be featured. Sadly if your taste is more esoteric than My Morning Jacket, it may not be for you. Somehow we doubt Mag