Posted by Doug Lacombe

For once I was right. Yup, I said it — a phrase that rarely leaves my lips and is generally disallowed at home by she who sets the rules. In an earlier column, I predicted Twitter would launch an advertising service and this week it did. Of course, a monkey could have predicted this (and, some would argue, did), but, hey, men aren’t often right — let me bask in the warm afterglow of smug self-satisfaction.

From @mashable: “Twitter has stolen the spotlight in the last week. It started off with the launch of a Twitter-built BlackBerry App and then escalated with the acquisition of Tweetie and the launch of Twitter’s ad platform.”

“Promoted Tweets” was launched at Twitter’s “Chirp” developer conference this week. PC World’s Tony Bradley described Promoted Tweets as being “like Google Adwords meets Twitter.”

This, of course, was inevitable. Only a chucklehead would think free Twitter was on-tap forever more. And when the Hollywood set adopted Twitter big time, corporate use had to come. Simply put, Twitter recently graduated to a form of mainstream media and with that maturity comes a business model.

Ev Williams, co-founder of Twitter, cited a few key metrics at the Chirp conference. From Liz Gannes’ (@lizgannes) GigaOM report: “105,779,710 registered Twitter users; 300,000 signups per day; 180 million uniques/month. And 75 per cent of traffic comes from outside twitter.com.”

Pretty mainstream with numbers like that, yet still nowhere near Facebook or MySpace.

While Bradley’s PC World article questions the value of promoted tweets, I see tremendous potential for passive branding, community building, contesting and more. Here’s a peek at what a promoted tweet looks like, in this case for Starbucks:

Bradley’s comparison to Google AdWords is apropos, for it has been such simple text advertising that has revolutionized the online ad business, I would argue commoditizing it in the process. The allure of cheap, tightly targeted and trackable advertising is nirvana to marketing folks.

Meanwhile, Twitter’s execs contend their efforts are best spent building the audience, a classic advertising play. This explains the launch of the BlackBerry application (now available in BlackBerry’s App World), and the acquisition of Tweetie, the most popular Mac/iPhone client for Twitter. The easier Twitter is to adopt, use and stay on, the more eyeballs for ads.

Several app makers have had a free ride thus far on Twitter’s infrastructure. Tweetdeck, Seesmic, Foursquare and others all benefit from the availability of Twitter and its open application programming interface (API). It will be interesting to see how much Twitter squeezes them out by building or acquiring its own apps and ad system.

As @lizgannes reported: “Williams laid out the company’s four core strategic priorities: infrastructure, friction-free, relevance, revenue.”

All are critical to the ongoing success and evolution of Twitter, but friction-free really grabs my attention. At Chirp, Williams demonstrated how typing “I don’t get” into Google, returns Twitter as the No. 2 result.

If people don’t sign on to Twitter or they abandon the service because it’s too hard to use, it will be difficult to build a sustainable ad model around it.