FAQ: Microsoft rents out Office 365

How much does a subscription cost? Home Premium runs $99.99 annually, or $9.99 when billed monthly. University is lots cheaper, just $79.99 for a four-year subscription, but you must be a full- or part-time student, or a faculty or staff member, at an accredited college or university.

What do I get? Office 365 Home Premium lets you install Office 2013 (for Windows) or Office for Mac 2011 (OS X) on up to as many as five PCs or Macs. Also included: 20GB of SkyDrive storage -- above and beyond the 7GB everyone gets for free -- and 60 Skype international calling minutes per month.

Office 365 University offers the same software and services, but allows customers to install the suites on a maximum of just two Windows PCs or Macs.

As long as you keep paying, you can keep using Office 2013 and/or Office for Mac 2011.

What applications do I get? Office 2013 includes the latest versions of Access, Excel, OneNote, Outlook, PowerPoint, Publisher and Word. Office for Mac 2011 has a more limited line-up: Excel, Outlook, PowerPoint and Word.

What do I need to run Office 365? On a PC, you must be running either Windows 7 or Windows 8; XP and Vista need not apply. A Mac must be powered by OS X Snow Leopard, Lion or Mountain Lion.

What happens to Office if I cancel the subscription or let it expire? Office drops into what Microsoft calls "read-only mode," which means that while the applications still run, they only let you read and print documents. The software cannot be used to create new documents, or make any changes to existing ones.

In other words, practically speaking the applications are worthless. Think of it as Microsoft repossessing the software, just like when the repo man drives off with your car if you don't keep up the payments.

Can I use Office 365 Home Premium or University for work? Absolutely not, says Microsoft.

The end-user licensing agreement (EULA) for Home Premium makes that pretty clear: "The service/software may not be used for commercial, non-profit, or revenue-generating activities."

Employees who want to run Office at home for work purposes must either purchase a perpetual license for one of the editions that do have commercial rights, such as Office Home & Business 2013 or Office Professional 2013 on Windows, or Office for Mac Home & Business 2011, or acquire a copy through their company's Home Use program.

Under Home Use, a copy of Office Professional 2013 or Office for Mac Home & Business 2011 costs $9.95. Contact your firm's IT department to see if it participates in Home Use.