Rated 4 out of 5 stars

Very useful for the older semantic markup supported. Really needs the new 2011 schema.org HTML microdata supported! Without this this addon isn't going to be of much use going forward as more web sites converge on the new standard.

See http://foolip.org/microdatajs/live/ for a site which live extracts HTML5 metadata. You can get the javascript source for that site from https://gitorious.org/microdatajs/

You can turn off the toolbar and use other mechanisms to access the different microformats. You can use a toolbar button, the URL bar or a status bar icon.

We're looking at microdata in the future.