The SIMILE Project at MIT produced a series of tools useful for in-browser screen scraping, namely Piggy Bank, Solvent and Crowbar. These projects now appear defunct; the website has had few wiki updates since 2008. The Firefox extensions no longer work with up to date versions of Firefox (3.6). Even the mailing list archives seem to have disappeared.
Is there anything similar available, or should I consider whether I can modify the relevant parts of the SIMILE codebase to work with contemporary Firefox?