> Writing documents, spreadsheets, taking inventory, sending and receiving e-mail.
Well... Outlook is already a web app, the rest of the Office suite will follow rather sooner than later, and inventory - it's either web apps or SAP, both memory hogs.
But not all businesses need to use the latest versions of Microsoft Office. They might not even need to use Microsoft Office at all. iPads come with a stock e-mail application, as well as word processing and spreadsheets etc. And if you're using old PCs, you can use old versions of Office. Or WordPad and an e-mail client. They are light-weight.