I love the concept of this but its unfortunatly not very helpful when you need your search to carry over to different pages of a site.
If you need it for really long sites with a lot of text all in basically the same place? this is pretty helpful

Works for me. But as it is right now, you need to re-enter the same words on every pages firefox loads. I wish it had a persistent keyword search option (if enabled) that will apply the current search to new pages as well.