This Monday marked the 15th anniversary of the birth of Hotmail. That July 4th launch date is no coincidence -- the service's founders intended its release to highlight the symbolism of its independence from more traditional e-mail models. The following year, the service would be snatched up by Microsoft and housed under the software giant's MSN umbrella. The subsequent years haven't always been easy for the brand, thanks in part to competition from Yahoo and Google-owned services. In 2007, the service fired back, revamping and rebranding itself as Windows Live Hotmail. It's been a decade and a half of ups and downs, but the webmail service continues t