Back in October 2010, Microsoft announced Office 365, the company’s first cloud-based productivity software product and, some would say, a direct response to Google Apps. On Sunday, Microsoft announced that Office 365 would now be offered as a public beta to both small businesses and enterprises.The small business beta is open for companies with up to 25 employees who need a solution that doesn’t require an IT staff, but still offers essential email, calendar, and website services. There is also an enterprise version for any size organization looking for more features and control, Office Professional Plus, Active Directory, and high-end archiving. Once an account is activated, which may take 2-4 weeks as part of the beta, users will have 30 days (from activation) to decide whether they would like to purchase the service or not.Introductions to both the small business and enterprise offerings are below. Small business owners are billed month-to-month starting at $6/user while those enrolling in the enterprise program have four plans to choose from starting at $10/user/month for the E1 plan. Currently, only the E3 plan, which begins at $24/user/month, is available in the public beta. All four (E1-E4) are described below.In conjunction with the launch of Office 365 to the public, Microsoft is also offering what it is referring to as the Office 365 Marketplace. The marketplace includes a number of recommended partners that are able to help deploy an Office 365 solution as well as other services and featured applications that can work with the productivity suite. For all of these (websites, collaboration, messaging, etc.) Microsoft promises 99.9% uptime which may ease fears by some companies who require a high degree of uptime in support of their business.Read more at the Microsoft Office 365 Blog, Microsoft news release and the Office 365 website.Brian’s OpinionI have really been surprised how long Microsoft has taken to offer a cloud-based productivity suite. I based this on its dominance with its client-based Microsoft Office suite, but perhaps it’s that dominance that caused the delay. The executives at Microsoft have taken a “wait and see” attitude before beginning down the road of offering a cloud-based version of Office. Unfortunately, while taking that pause, Google went ahead and offered their own cloud-based apps and almost certainly grabbed some early customers who would have considered a similar Microsoft offering.Google had one great advantage which enabled it to launch Google Apps first: it didn’t have to worry about undermining an existing (and hugely profitable) product. Microsoft does have to worry about that. They could lose a considerable amount of revenue if there is a fast shift to the online offering for Office rather than the traditional client-based software. In return though, Microsoft does gain the holy grail of revenue for a software company: subscription revenue.Microsoft has for a long time been trying to move companies to a subscription model. Companies that currently sign up for a Microsoft Enterprise Agreement must commit to deploy a desktop-based product such as Windows 7, Microsoft Office or client access licenses to all business PC’s. Microsoft previously only offered perpetual licensing for this agreement which means if you terminate the agreement you are no longer entitled to upgrade rights, but you get to keep the software and any previous upgrades you received. Now, Microsoft EA customers have a new subscription option which entitles them to software and upgrade rights like the perpetual program, but the big caveat is if you walk away from the agreement you walk away with nothing which encourages companies to continue their subscription. Office 365 is clearly an extension of this subscription business model by Microsoft to guarantee revenue annually.