Google has quitely introduced a Powerpoint presentation/slideshow preview feature to its Gmail webmail service, reports Google Blogoscoped. Google already supports preview for Word documents and Excel spreadsheets as part of their Google Docs & Spreadsheets program. With this addition, Google GMail now supports three most commonly used Microsoft Office programs for online viewing.

When you receive a Powerpoint attachment, GMail will show a “View as Slideshow” button. When you click that, the presentation is loaded in a new browser window. Since the slideshow is Flash based, you can right click on it to open a context menu, which allows you to automatically play the presentation, among other features

Note: Office 2007 formats are not supported