If you are the type of person that is taking a close watch on the number of outbound links you have Firefox Addon LinkCounter is very useful as it shows you the total number of links, a breakdown of these if they are internal within the same site or external going to other sites, and it has the option for you to copy them all if you need to paste them in a separate document.
LinkCounter Firefox Addon for Firefox 3
If you liked this plugin and is already running Firefox 3, you may not even find an old version download link on the official Mozilla page. Anyway here is a modified LinkCounter.
This is NOT the official LinkCounter update for Firefox 3. This was just modified to work with Firefox 3 and I suggest when the official upgrade comes out, replace this one.