resizer & cropper
could be implemented on client side via html5 canvas.
i tried, but the only problem is easy to use interface.
screen size and actual workspace size are available for script.

download search results as zip archive, but requires web server assistance for adequate performance

all tag changes for past n hours or since last viewed. for aggressive monitoring (not for me). also may be useful some marker of last viewed comment.

option to hide avatars and all unnecessary images

// none of these suggestions are really needed. better performance is more valuable