Adriaan describes it best:
“1001 is a desktop client to be used in conjunction with Flickr, the online photo-sharing website. 1001 not only uploads photos to your Flickr account, it notifies you anytime new photos from either your contacts, everyone, or your favorite tags are uploaded. 1001 allows you to step into the stream of photos passing through Flickr and to quickly see what’s new at the moment. Just run the app in the background and if triggered, 1001 pops up a small unobtrusive window to notify you of new photos.”
Check out the 1001 site for more information, screenshots, and to download.