Puntuado con 1 de 5 estrellas

You don't need this.
Simply create a keyword like 'goback'
with the url:
http://web.archive.org/web/*/%s

Then just type goback followed by a space and the domain for the site you want.
example: goback yahoo

This will bring up the Wayback machines archive of the site, you can then add the rest of the path for specific page in the native Wayback search form at the top of the page.

Puntuado con 2 de 5 estrellas

It doesn't work for addresses with paths, as it turns the slashes into escape codes: (/ turns into %2F), which don't work on the wayback machine.

Esta valoración es de una versión anterior del complemento (20100602). 

Puntuado con 5 de 5 estrellas

Awesome site - this makes it very easy to reference!

Esta valoración es de una versión anterior del complemento (20100602).