This slideshow feature of GMail will be useful since you no longer have to download the full PPT attachment in order to view that 16th slide of the presentation.
Here are two additional situations where it may help:
1. If you have to view a presentation on some computer that has no copy of PowerPoint, gmail yourself the PPT file and watch the slides inside the web browser. [similar to converting PDF to text using GMail]
2. GMail converts every slide of your Powerpoint presentation to a Flash (swf) file - if you manually advance the entire PPT slideshow using the arrows, all the slides will become available as Flash files in your browser's temp folder.
Just a quick way of transforming Powerpoint slides into SWF documents without using any desktop conversion software. The swf files may then be embedded in your blog for sharing with readers. Nothing great since Scribd can also convert your PPT to Flash paper.
Do you know GMail Powerpoint viewer can read PPS (Powerpoint Show) formats as well.
Written by Amit Agarwal