Original Link: http://wp.tutsplus.com/articles/tips-articles/quick-tip-add-extra-media-type-filters-to-the-wordpress-media-manager/

By default the WordPress Media Manager allows you to filter media by three types only; Images, Video and Audio.

The site I am currently developing will use a lot of PDF attachments, so I wanted to add PDF filtering to the media manager.

Handy to advice to know for adding other media type filters to the WordPress Media Manager..