This is one of the main reasons why we launched crocodoc.com, to do the same thing to Adobe Acrobat that Gmail did to Outlook: Take a bloated offline application, bring it online, make it easy to use, and make it accessible to the masses.
When you think about some of the most common reasons why people use software like Acrobat and Word (e.g. viewing a document, filling out & saving a PDF form, commenting on a presentation with a group), these are all things that should be easy to do online or on your mobile device. That's the vision we're working towards at Crocodoc: view and collaborate on any document on any device.