RDFa tools

Hi Ben and al,

I remember that time ago I installed the firefox plug-in for RDFa files,
called Fuzzbot (http://rdfa.digitalbazaar.com/fuzzbot/).

As I changed computer I was trying to install it again, but I could not
succed... do you know if it works on particular releases of firefox?
Is this really needed? http://rdfa.digitalbazaar.com/librdfa/ 

Any other tool available?

Thanks
Margherita