TechCrunch are (tongue-in-cheek) calling this site 'the future of mashups', which should ensure that the site is inundated with visitors. The site is a Google Maps mashup of pizza restaurants that uses crowdsourcing to locate the best pizzas. The most important thing for a site that wants to crowdsource reviews is - a crowd. The TechCrunch coverage should help get that started.
Searching for restaurants on the map is very easy. Just type in a location or zip code and press enter. Pizza restaurants are then shown on the map. The bigger the map marker the more recommendations the pizzas have had.
Using the marker size to represent popularity is a very cool feature and works very well. apparently some other cool features are in also in the pipeline, like tagging and microblogs for each pizzeria.