Google launched the slideshows feature for Gmail. It is a new feature in Gmail that lets you view the attached PowerPoint presentations as a slideshow, without having to download it to your computer.

To open a Microsoft PowerPoint (PPT) file without downloading it to your computer:

1. Open the message containing an attachment.
2. Click “View as slideshow” at the bottom of the message.

This will open your slides in a new browser window where you can view your PPT slideshow using Google’s Flash-based player, without ever needing to install PowerPoint. You can navigate between slides by clicking the left and right arrow buttons at the top of the screen, or by choosing a specific slide from the dropdown menu in the upper right corner of the screen. For more information, visit Gmail Help Center.