There you can open it and edit it anywhere with a web browser or a copy of Office 2013. Additionally, there are free PowerPoint apps on Android, Windows Phone, iPad and iPhone.

When you convert Keynote files to PowerPoint, you can allow collaborators without Keynote to open presentations on non-Apple computers.

SlideAware works with PowerPoint to put your presentations on the Web.

Thanks to an intelligent suite of applications, called Office Web Apps, PowerPoint presentations fall right into this category.

Haiku Deck lets you tell your story in pictures rather than text-laden slides. It's easy to share your iPad presentations and export them to PowerPoint and Keynote.