What makes it to be special is that it downloads photos from Flickr to set them as your allpaper, so you'll always have a new and surprising wallpaper.
You can set the time each wallpaper wil be set as well as the position (center, stretch, mosaic)
Of course, you can decide tags and users for Flickr options. That's great, you can select, for example, beach and you'll always have a new wallpaper featuring beaches.
Finally, you can set other advanced settings for that search, such as, relevance, interest, date, etc.