Becoming a punch line within a mere month of one’s launch is a rarified achievement. And yet, that’s what Google+ managed. The perception that Google’s social network is a ghost town persists a year later, despite its having 400 million accounts and 100 million monthly active users.

Even the guy in charge of the product, Bradley Horowitz, made a joke to that effect onstage at Business Insider’s Ignition conference today. When the interviewer asked the audience how many had used the social network in the last two weeks, Horowitz jumped in with a sarcastic, “Thanks, you two,” implying only two people in a crowd of several hundred had raised their hands. (In reality it was slightly more than two.)

For the last year, Google has been torching once-sacred convictions around its golden, money-printing goose, the search engine, to prop up Google+. Now, a year into the debate over whether Google+ is the ghost town everyone thinks it is, or if people besides Robert Scoble actually are using it, Horowitz is clinging to search more than ever.

Onstage he described what’s wrong with the ads on Facebook and other social networks (but mostly Facebook). Facebook ads, like banner ads, are interruptive and don’t include intent, even if you’ve volunteered that you like a certain brand. But hey! You know what form of advertising does have intent? Oh yeah, just one: search. The No. 1 form of advertising online, and one that happens to be dominated by Google.

Google+ may not be a great social network, but damn if it isn’t searchable. Searchable means monetizable. “The philosophy is, there is a form of ads that’ll be useful for users,” Horowitz said. “We don’t have to make next week’s payroll based on jamming ads at users in an inappropriate way.”

Facebook, and other digital marketers would say that yes, search is awesome and effective, and social search is also awesome and effective, but that’s only one part of the marketing funnel. Facebook would say it is going up-market to discovery, and branding, and all of the things that happen before we type “Lululemon yoga pants” into a search engine, wherein a hundred blogs and aggregators fight over last click attribution pennies.

Interviewer Nich Carlson said exactly what I was thinking: “That sounds like a great argument for Facebook to build a search engine as fast as possible.” The company has hinted at the possibility of making search a bigger part of its monetization strategy. Once it does, the battle over social search will really get fun. Conspiracy theorists in the ad world say Facebook’s search box has sneakily gotten larger and larger with each site update over the years.

But Horowitz had a zinger ready: “[Building a search engine] turns out to be pretty hard.” Touché, Mr. Horowitz. Touché.