Flickr - When you enter a comment on in all caps, the comment is posted with proper capitalization.
/via Russell Heimlich
Flickr - When showing possession (I.E. Little Big Details’), the extra ‘s’ is truncated.
Flickr - The favicon turns into a live indicator showing the progress of the upload.
Flickr - Error message when you exceed the 140 characters limit when posting a photo on Twitter.
Flickr — When uploading files, it shows percentage in the tab, so you can always see the load progress while surfing other sites.
Flickr - As your cursor moves into map and into location marker, the map zooms from nation to region to street level.