Today we've launched happytables ( http://www.happytables.com ), a squarespace / wordpress.com for restaurants. I had posted on HN before about a previous iteration we performed ( http://bit.ly/sn0FWc ), and am really satisfied how far we've gotten with it all.
The entire solution is built on top of WordPress, it's allowed us to quickly prototype and build various components. It'll be interesting to see if other solutions pop-up for unrelated niche markets using WordPress too (i.e. real estate, sports clubs, etc.).
Would love to hear your feedback on our concept and would gladly answer any questions too...