Microsoft announced Wednesday that its consumer-targeted Office 365 Home Premium subscription service has reached a user base of 1 million just 3.5 months after its launch. Microsoft lauded the number as proof that its grand vision of subscription-based software is taking hold. Although first launched in June 2011, Office 365 was initially targeted to business customers who sought a way to license up-to-date versions of Office alongside syncing and Exchange capabilities. Late last year, the company announced its plans to…