In the spirit of Microsoft's reboot, the new version of Office is more complex for business than it used to be. It includes much more than familiar software like Word and Excel, extending to Office servers (Exchange, Lync, SharePoint and services that run on the latter like Excel Services, Project Services and the Office Web Apps).
There are also hosted versions of these services, provided through third parties and Microsoft itself, as with Office 365. (From March you will also be able to buy Office 365 through Microsoft partners).
Now including hosted online services for company servers, Office 365 provides Office Web Apps and the Outlook Web app as part of this service with subscription licenses to the actual software useable on personal desktops.
Additionally, Microsoft has launched Office 365 Personal, which is intended for a single user and can allow one download of Office. The consumer, Office 365 'Home Premium' service, costs you $99.99 a year (£79.99, AU$119.99) for Word, Excel, PowerPoint, Outlook, OneNote, Access and Publisher.
That's good value if you share it with the family; up to five people in the same household can have their own installations of Office on their PC or Mac at the same time (for the Office programs that run on a Mac – and Mac users get the current version of Office for Mac until a new release comes along in the future). And when the next version of Office comes out, you'll get it on the same subscription.
All five people get an extra 20GB of storage on SkyDrive to keep documents on and 60 free Skype world calling minutes a month (which can be calls to a landline or a mobile and from your PC or from a smartphone with Skype installed).
You can download the Office programs temporarily on another PC if you're away from your usual PC (even if it already has another version of Office installed). So if you have a document on a USB drive or on SkyDrive that you need to edit on another PC, and using the Office Web Apps from SkyDrive doesn't provide of the features you need (like seeing revision marks in a tracked document you're collaborating on), you can use Office on Demand to get the full version of Word in just a few minutes.
You manage all this from the revamped Office.com and there's a link to your account there in the ribbon of all the Office applications. (To activate the Skype minutes you have to link your account to the Microsoft account you're using for Office 365, which can be done on the Office.com site.)
You also get a list of your recently edited documents, which helps when using Office on Demand to give it a fresh edit.
If you're at college or university (or you teach at one) it's possible to get Office 365 University on a four-year subscription for $79.99 (£60, AU$99) that you can use on up to two PCs or Macs.
Office 365 for business
Microsoft offers three tiers for businesses with less than 300 seats. Office 365 Business Essentials allows you to use online Office Apps only (no desktop applications) plus 1TB of online storage per user and a 50GB inbox with email, calendar and contacts functions for £3.10 ($5, AU$5.61) per month per user on an annual contract.
Office 365 Business offers Word, Excel, PowerPoint, OneNote, Outlook, Access, Publisher and Lync, with a subscription licence for each user to run them on up to five PCs or Macs at once. You get regular updates and new features for the software and the Office on Demand option lets users download Office to any PC they're using temporarily. You still get the online storage but no email services.
Office 365 Business Premium combines Office 365 Business and Business Essentials.
For larger companies, Office 365 Enterprise has the full Office 2013 set of features in both the desktop software and SharePoint, Lync and Exchange Online services, like public folders, legal hold, data loss prevention and rights management, to protect confidential information, as well as archiving.
If you're already using Office 365 on an enterprise plan (or the simpler kiosk plans for users who don't create content), Microsoft has tweaked its offerings into Enterprise E1, Pro Plus and Enterprise E3 so users can edit documents in Office Web Apps in all plans.
Enterprise customers will get Yammer integration and be able to purchase the Project Online service when they're available later in the year.