Web surfing increases your risk of having malware installed on your computer.

WSJ: Hack Attack: How to Protect Your Online Accounts

And as I mentioned earlier, you're getting the full version of Office installed on your computer, not a copy that runs on your Web browser over the Internet.

NPR: Review: Microsoft Office Pricey, But Good Value

Think of it this way: before, if you wanted to type up say, your resume, you'd use the word processing program you have installed on your computer, but now?

NPR: Will 'Cloud Computing' Work In White House?