Zipingo joins the ranks of local business review and ranking services such as Yelp, Judy’s Book (which just raised $8 million from Mobius Venture Capital, Ignition Partners and Ackerley Partners) and idealab’s Insider Pages.

Like the other sites, Zipingo aims to pair yellow page-like contact information for local businesses with user reviews. It was created (and owned) by Intuit.

Since all of these sites are well done, have similar feature sets and have financial backing, it will be very hard for any of them to gain enough critical mass to dominate the market. This is certainly an attactive space (combining local advertising with the potential for premium listings).

However, it’s my belief that a single, open API (in and out) yellow page service, with consumer ratings, could dominate this market very quickly. As great as these services are, they rely on centralized content and getting users to come to them to both write reviews and find a business. An open service could have an easy way for businesses to insert their listings (and pay for enhancement), and anyone could take the data via an API (enhancing the network effect many fold). I wrote about this very briefly last week in a post about companies that I’d like to profile but don’t exist yet (no. 7 on the list).

Back to Zipingo and the other related services, if there are any dedicated users who’s seen a unique feature or have noticed heavy user participation, please ping me.

Riffs, a review site for anything, launched quietly last week.

It takes a hybrid wiki/social bookmarking approach. Any user can add a URL to begin a discussion (or just begin a discussion without a URL), and the Riffs community votes on the thing and discusses it in wiki fashion. All pages have RSS and the clean interface has some great Ajax features. Riffs also has tagging, including “common tags”, which I think is interesting.

So why don’t I like it?

It’s centralized content. All of the content resides on Riff’s servers and they require people to go to the site (in one way or another) to add content to the discussion. And in this case it seems absolutely crazy to architect their service this way.

Reviews are everywhere on the web today. And the most exciting place to find reviews in on blogs. Try it – search on “whatever” and “review” and you’ll see thousands upon thousands of high quality reviews on just about anything all over the blogosphere.

Riffs approach is to try to get in the middle and generate a centralized discussion by people who want to talk about a subject. They are staying as open as possible by creating RSS feeds for each page, and my understanding is that they may be creating tools to allow people to push the content they create at Riffs out to their blog, like flickr does.

And it seems to me this is their core mission – to become the flickr of reviews. Not “flickr” in the joking way that everyone says when something is trying to be the cool new web 2.0 application, but literally, the place people put their review content and then pull it out for their blog if they choose to do so.

Fred Wilson writes about the service and addresses points similar to those above that I made on CrunchNotes and Jeff Jarvis made on his blog.

Jeff and my point: Blogs are the place to write content. Microformats and tagging will help people do this. My additional point: And they already are doing it, at massive scale.

Fred’s retort::

But as a content creator living on the edge, I am not sure we are ready for microformats and tags and social interaction to do all the work for us. We’ll get there, I am sure of that, but we need an interim step and that step are services that feel centralized but are really application specific edge feeders. I need a better word for these services, but for now I’ll call them the edge feeders.

I disagree with Fred on this. Flickr is a useful “edge feeder” because it has tools for managing photos that go way beyond what most bloggers have. And more importantly, they host the pictures for you at no cost.

Reviews are different. They are easy to write, easy to publish and cost very little to host. What we need is a service that takes all of this great content out there and pulls it into a centralized place for search and find (and further discussion), but which always points people back to the original post.

Back to Riffs, I really do like the wiki/communit aspect of the service. But they need to find a way to grab their data from the edge first and foremost. If they can do interesting things with it, then they can be successful.

I know why they aren’t doing this. All that open data out there…anyone can take it. If Riffs is successful with my suggested approach, what stops others from doing the same?

My answer? Absolutely nothing. But their current approach doesn’t even put them in the game. I say find a way to aggregate that data and relate it into a discussion somehow, like Memeorandum does on a smaller scale. Then you’ve got a big company.

But you better hurry up. Some guys are already circling the wagons.

Company: Yelp
Launched: in Beta (since late 2004)
Location: San Francisco

Yelp is a website that allows users to write and share reviews of local businesses. It also has social networking features (adding friends, groups, etc.) to share reviews with a trust network. The idea is that people generally trust their freinds’ recommendations.

All of this user-generated content on local businesses, combined with the Yelp search engine, also provides great inventory for Yelp to sell local businesses contextual advertising.

The basics of Yelp: create an account, fill in your profile, add friends and write reviews. Yelp attempts to auto-fill the business information on a new review. The review consists of a 1-5 star rating and a free text area.

Searches bring up local businesses based on your zip code and include paid advertising above reviews.

Yelp is available only in San Francisco currently and plans to expand to other cities over time. They are also rumored to be closing on a Series A financing.

There are a number of other companies that are targeting local business reviews in an almost identical way. For instance, check out Judy’s Book, profiled previously and idealabs’ InsiderPages.