Just five months after launching Oink, San Francisco-based start-up lab Milk, run by Digg founder Kevin Rose, has decided to shutter the app after an unsuccessful outing.

We started Milk Inc. (the company behind Oink) to rapidly build and test out new ideas, said Milk in a note on the Oink website. Oink was our first test and, in preparing to move onto the next project, we've decided to shut it down to help focus our efforts.

Oink, which was the first project created by the San Francisco-based start-up lab, looked to revolutionize the way users rank and discover places and items. Oink blended review sites like Yelp and location-based rewards programs like Foursquare to create a system where users could rank anything within any store or location.

The idea sounds extremely simple, but it was also extremely promising. For instance, if you wanted to know the best thing to buy at a specific coffee shop, Oink would tell you. If you wanted to know the best rollercoaster at Six Flags, Oink would tell you. Anything and everything could be rated in Oink, giving users a much more personal and specific recommendations engine.

In saying goodbye, the company posted a thank you message on its website.

Thank you so much to everyone who joined and contributed to Oink, Milk said. You have been the heart of Oink. We are extremely grateful for all of your effort finding and rating the best things in the places around you. We've discovered thousands of awesome pizzas, pastas, coffees, teas... and roller coasters, zoo exhibits, paintings, sculptures, vistas... and sodas, salads, sliders, soups... and so much more.

When Kevin Rose founded Milk in April 2011 -- just weeks after he'd resigned from Digg, which he founded in 2004 -- there was a great deal of excitement surrounding Rose's next big mystery project. Rose had bought an office in San Francisco's Mission District, found an elite team of less than 10 people, comprised of coders, designers and thinkers, and sought to tackle a small number of the biggest and oldest industry problems using the mobile Internet.

Rose wanted Milk to be an incubator for ideas, not start-ups. 

We've been upfront with investors that the lab's companies are going after big ideas, not launching continuous small projects, Rose said. There is so much opportunity to disrupt old media and old business.

Milk raised about $1.7 million in seed funding from investors like Ron Conway, True Ventures and TechCrunch founder Michael Arrington, even though no investor knew what Rose was planning.

Then, on Nov. 3, Rose unveiled Milk's very first project. Oink attracted plenty of attention, promising a completely user-generated app experience, and even landed a new investor in Google Ventures.

We started talking to Google after we closed our round, but decided to open it up for them as they've been adding a ton of value right away, Rose said.

The partnership made sense, since Oink also leveraged the power of Google Maps so users could find new places based on rank items.

We're going after a more granular experience, Rose said. Our main goal is just to prove out the concept that people just want to rank and rank the things around them.

Unfortunately, Oink never caught on. Even though Rose said his app had been downloaded about 150,000 times by December 2011, one could assume that the issue with Oink wasn't if it was downloaded, but if it was used. Milk gave no official reason for its decision to shutter Oink.

However, Oink's death does not mean that Rose and Milk are failures. Oink was a great idea, but there could have been any number of reasons as to why it didn't work out. Maybe it wasn't the right time, or didn't have the right support, or advertising. Maybe it wasn't a good idea. Or maybe people just didn't know about Oink.

Either way, this is not the last we'll see of Kevin Rose or Milk. Rose, who is only 35 years old, has plenty of clout in the tech industry and still boasts an enormous fan base, including more than 1.3 million Twitter followers. Rose will have a following regardless of where he goes or what he does.

Rose will eventually return with a new project or app that truly disrupts the industry. There are plenty of decrepit industries that need change, and Rose has a good head on his shoulders. Rose wants to solve problems, not just make money, and Milk's small, focused team is the right group to take Rose's ideas to the next level.

Oink will serve as a valuable lesson for Rose and the rest of the Milk team. Rose will have a chance to learn from its failure, and take those lessons into the next big project he decides to produce. Oink was a good idea, but people could live without it. The best services exist because people didn't know they needed them (see: iPods, iPads, the Nest thermometer). In the case of Milk, one hopes the sequel is better than the original.

The Oink app and website will officially be shut down on March 31. Milk tells all Oink users they can download their ratings and pictures by entering their username or email address associated with their accounts.