Given the number of users and $50-a-year subscription fee, it's hardly a surprise that Microsoft is pulling in a ton of cash from Xbox Live, but it looks like the service has recently crossed a significant milestone: the $1 billion mark. That's what Bloomberg estimates, at least, based on the number of paid users (about 12.5 million), and a recent statement from Microsoft's Dennis Durkin, who said that sales of downloadable content had topped subscription revenue for the first time. That translates to about $600 million from subscription revenue, and at least $600 million from other sales, for a grand total somewhere north of $1.2 billion. Can't really blame Sony for