Get On Your Soapbox
Rafe pointed out this slick community review site (built with Rails!). What's cool about it is that you can point it to your blog feed and it will import appropriately tagged posts as new reviews, so you don't have to remember one more place to post stuff. I can see that idea catching on fast, even if the site itself doesn't.
Their choice of implementation is interesting though. Just add an empty span tag with a particular class (indicating a postive or negative review) to your post content. Isn't this what RDF is for?