I've been meaning to add the RVW module for reviews for a wee while now and tonight I did it. RVW is an RSS module created by Alf Eaton. It's basically some extra metadata you add to your RSS feed that describes reviews - of books, music, anything you like really. Reviews is one part of Marc Canter's crusade for open microcontent formats.
Alf has created a plug-in for Movable Type that I installed tonight. It was relatively straight forward, except for one slight puzzle that had me chewing my pen for a bit. In order to 'force' your RSS feed to include the RVW metadata, you need to add a little something to the URL for the book/CD/whatever you are reviewing. Basically you need to add a 'title', with the rating data, to the link tag. Like so:
<a href="http://www.amazon.com/etc" title="The Coma - rating:6">
If all goes well, your RSS feed will now include the RVW metadata. Take a look at my RSS feed, for my previous post - a review of Alex Garland's book The Coma. Look for the <rvw:item> tag, within the <item> tag of that entry.
Of course if lots and lots of people add RVW metadata to their RSS feeds, then we can start to aggregate reviews data from all over the Web - a bit like All Consuming already does as a web app. I think at the moment few people are using RVW, mainly because it takes some geekery to install the MT plug-in. Most other tools like Radio Userland don't yet support it (as far as I know), but apparently one called Blogware supports it out-of-the-box. So it'll take more tool vendors like Blogware to add support, more folks like Marc Canter to evangelize the good work of developers like Alf, and more geeks like me to be early adopters... and then eventually open reviews will be a reality.
Update: It's not mentioned in the documentation, but you also need to add a bunch of namespace declarations to your RSS 2.0 feed. Here's what I added, based on what I saw on this page over at Alf's:
<rss version="2.0" xmlns:ent="http://www.purl.org/NET/ENT/1.0/" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:rvw="http://purl.org/NET/RVW/0.2/" xmlns:foaf="http://xmlns.com/foaf/0.1/">