Ever been on a computer that did not have PPT installed (it’s rare, but does happen). You can install the PPT Viewer from Microsoft or if the presentation is simple you can just send it to a gmail account.
Within Gmail (Google’s email application) an email with a PowerPoint presentation can now open PowerPoint attachments as slideshows, without having to download anything. Just click “View as slideshow” next to the .ppt attachment you want to preview. It only views the legacy format .ppt, so no PowerPoint 2007 (.pptx) presentations yet.
– Troy @ TLC