As Ronny wrote this morning, Yelp CEO Jeremy Stoppelman walked away from a $550 bid from Google this weekend. Apparently, the two parties had agreed to the price and were in late-stage negotiations, but then something happened and Yelp notified Google that they were not going to sell.

At first glance, this seems like a Jerry Yang-esque all-too-bold a move for a content company at a time when content has no business model. But Yelp has a lot more going for it than page impressions. As a location-based content play that impacts the purchasing decisions of its enthusiastic users, the company is in the right place at the right time.

What Yelp gets right:

1. Unmitigated user-generated content is unmitigated crap.

This is one reason YouTube was a questionable acquisition for Goog. Since being bought, it's struggled to make money and has shifted strongly away from cpm plays to big deals with big media companies. But Yelp has religiously filtered out noise from the beginning. If you can take the best of UGC, and train your users to create quality, then you’ve got something. Apple’s notoriously oppressive approval process for its app store causes consternation among developers, but it also makes it useful to end-users. Yelp saw this early on, hired a few good writers to set the tone, and took pains to train its other writers. This translated into brand loyalty.

2. Location, location, location.

The geo-web is cracking open revenue streams at a time when venture-backed tech companies are parched for cash. Everyone knows billions of ad dollars have left print and TV, but they haven’t gone online, and entrepreneurs with ad-based biz models are now turned away at the VC office door. Virtual goods are the new panacea for web-based startups. That’s great, and the market is getting appropriately crowded, but an ephemeral market can only be so big. Concrete things in the real world still matter. Bellies are not virtual.

Yelp was integrating the "real" local world, the social graph and the online world before anyone realized how big location-based mobile services would be (the market was recently revised from $15 billion to $60 billion). As companies like Foursquare scramble to go viral, Yelp can flip a switch and make its soft opinion map of the world’s eateries available to any service. That’s valuable.

Advertisers know impulse buys are where ads are most effective, and there are few impulses that hit consumers as consistently as hunger, and few decisions more commonly made based on recommendations from friends and trustworthy strangers.

3. Stay close to the cash register

There was a time when growth mattered more than revenue. Boost your traffic, and trust in the coming ad-dollar deluge. That didn’t happen, then the recession hit, and the startup world switched gears. With a register at every diner, Yelp has always been close to cash.

Google is still the best acquirer

For years, Google has contracted people to approach local businesses about maintaining their contact information on Google Maps. Goog realizes that for some info, you just have to get a van and drive around everywhere, or get tons of people to go harvest data. This means they already have contacts with tons of local businesses, which is fodder for its ad network and exchanges. Goog’s small business sales database positions it well to attack the geoweb. As Android penetrates the mobile market, millions of Mom and Pop diners around the world will redirect their ad budgets previously spent on a spot in the now-defunct Pucksatawny Ledger to get on the mobile device of every tourist passing through and every local family going out to dinner. The trick of course, is getting there at the right moment, and only users can tell you when they’re looking for grub. Browsing to a trusted restaurant review site is a pretty darn good indicator of intention.

Brand name is powerful in this context. Yelp is arguably the most widely trusted brand when it comes to location-based consumption. Yes, Zagat is up there, but it’s a bit highfalutin—Yelp is for every hunger attack.

All of this makes Yelp a good target for Google.

Apple doesn’t buy content except in a few extreme cases when there’s key technology and connections that could hurt a core piece of its business. Lala was not just a content buy. It was a threat (offering music for 10 cents is a serious undercut), and a strategic technology grab (Apple needs iTunes in the cloud).

Microsoft is the strongest counter-suitor, but its mobile push has floundered. According to Admob, Windows Mobile accounts for about 2% of smartphone traffic, whereas Google’s much younger Android accounts for 16% and rapidly growing. Microsoft has discovered that entertaining deals with content companies like News Corp is one way to weaken Google’s dominance, and they would certainly like to see Yelp escape Mountain View’s grasp.