The eBay part assists in how the visited links works on their discussion board and sets the image maximum width to smaller so when posters link to a too large of a picture it will not break a thread. It also sets the body width to assist those with smaller screen resolutions and does some other formatting like text and url font size. This looks fairly nice with the Remove It Permanently, Yet Another Remove It Permanantly (YARIP) or Platypus Firefox addons which can remove all four outside areas of that forum and other page elements.

This has some miscellaneous features. It hides the greasemonkey icon in the lower right of the browser - can still use the Tools. It also hides the toolbar borders and highlights in a misty rose when taken to https.

Code specifically for the eBay forums and to use with Greasemonkey and Remove It Permanently and YARIP can be found here. The 2nd post is for the Yet Another Remove It Permanently (YARIP) addon that seems to be the best so far.
http