Automatically previews pdfs, powerpoint presentations, and other documents in Google Docs Viewer. By clicking on a link for a supported document format you'll be taken to the Google Docs Viewer. No more downloading large files and launching another application just to view it.
The Google Docs Viewer does not work on files that require a log-in to view, but you can make it ignore specific domains in the options so you will still download the file.
On the options page you can also disable any file formats you don't want to use the Viewer for.
Please note that Chrome now has a PDF viewer which is separate from this plugin. If you prefer to use Google Docs to view PDFs then you can enable that in the options.