As requested by several users; there is a new section documenting metadata supported by Diffractor.

Diffractor can add or update metadata such as tags, rating, description or dates. It can also understand metadata added by your camera. Diffractor has a database to cache these values for faster searching. However, the values are primarily stored in metadata to allow compatibility with other programs.
Diffractor 116 2016-01-05
Diffractor 116 final release is ready for download. Same new features as the beta with a few minor bug fixes. Enjoy!
Diffractor 116 Beta 2015-12-01
I am happy to announce the next version of Diffractor is in Beta: http://www.diffractor.com/DiffractorSetup.Beta.exe

Been a long time so the list of improvements is long:
  • Searches can now filter on media type with new photo|video|audio keywords. For example 'Photo C:\Users\zac\Pictures' only shows photos in that folder.
  • Keywords in searches can now be identified with a # symbol. For example '#tree' shows my all items tagged with tree.
  • Files in sub-folders can be show using ** query syntax. For example 'C:\Users\zac\Pictures\**' lists all the items in sub-folders.
  • File globbing can now be used on folders. For example 'C:\Users\zac\Pictures\*.jpg'
  • It is now possible to add negatives to a search. For example '-London' searches for items without the text 'London'.
  • Files with Duplicates or sidecars (external thumbnail, xmp or subtitles) are indicated with a small number icon.
  • Added a new related media search to show duplicate or related items. For example 'related:C:\Users\zac\Pictures\family.jpg' shows duplicates and images with similare date and location properties.
  • Sorting by camera or Megapixels has been added.
  • 'Open with' integrates with windows to get a more accurate list of compatible applications
  • Viewing properties for multiple selected items now possible. Previously only show properties for single focus item.
  • Performance greatly improved by switching to Direct3d 11. Unfortunately this means dropping support or Windows XP and Vista. Sorry XP folks.
  • Fixed selection of multiple items using control or shift keys.
  • Added buttons on screen to allow moving to the next or previous media item.
  • New layout of controls related to playing and viewing media.
  • Added ability to edit common/favorite searches or folders.
  • Added tooltips in many areas to help users identify what a given button will do.
As usual report any problems here.
Diffractor 112 2014-05-16
You may have noticed version 112 has been released. It is just a bug fix release containing the following:
  • Fix for crash on some older graphics cards.
  • Improved start-up performance.
  • Fix to encryption of flickr/facebook credentials.
  • Improved searching performance
  • Changed install so admin rights are no longer required.
  • Upgraded libav and sqlite
Great news, Diffractor 111 is ready for prime time, it can be downloaded here: http://www.diffractor.com/DiffractorSetup.exe

It has several bug fixes to improve stability. It also has more intelligent sorting. Security for Twitter, Facebook and Flickr uploads has also been improved. Enjoy!
Diffractor 111 Beta 2014-02-22
Download the next version of Diffractor here. It has several bug fixes to improve stability. It also has more intelligent sorting. Security for Twitter, Facebook and Flickr uploads has been improved. Enjoy!
A survey by the Diffractor project found most users still storing their media collections on a PC. Diffractor, a new Windows Desktop App, helps to keep them organized.