Ok, I might be a little slow on this but I recently downloaded and installed GreaseMonkey for Firefox. GreaseMonkey is an extension that allows you to run user scripts on particular web sites.
There are over 200 user scripts available. For example, I like to use Titan TV to check out what’s on the tube, but they have a really annoying advertisement that runs the length of the page. It must use some sort of JavaScript because it causes Firefox to jam sometimes. But there is a user script that I installed into GreaseMonkey that removes that banner every time I visit Titan TV.
I like to use Del.icio.us to save my bookmarks. One of the issues I have with Del.icio.us is that on my list of bookmarks there is an edit link but not a delete link. It takes me another click to get to the Del.icio.us provided delete link. Conveniently, there is a GreaseMonkey script that adds a delete link right next to the edit link by each of my bookmarks.
I use Bloglines to read my RSS feeds. They have a clipping feature which allows me to save a particular entry to go back later and read. With this GreaseMonkey script I can clip entries to Del.icio.us instead. That’s more convenient for me.
Good stuff!