Yesterday, Twitter promoted Chief Operating Officer Dick Costolo to its CEO spot. An initial public offering probably isn't far behind.

Fools might already know Costolo, a former entrepreneur and Google (Nasdaq: GOOG) employee. Last November, he teased Twitter's business model at an event hosted by TechCrunch.

"It will be fascinating," Costolo said at the time. "Non-traditional. And people will love it ... It's going to be really cool." Now, he gets the chance to make good on that promise.

In a blog post announcing the change, co-founder Evan Williams said that Twitter has embarked on a small-yet-successful "monetization effort," and that Costolo would take over the reins to lead growth. Williams will join co-founder Biz Stone in thinking big about what's next for Twitter.

My guess? An IPO.

There isn't much choice, is there? Twitter has already rebuffed buyout offers from Facebook and Google, yet it has investors who've put in money at a $1 billion valuation. Nothing less than a large public offering -- something on par with United Parcel Service's $5.5 billion IPO in 1999 -- will likely satisfy these late-stagers. Unfortunately, we have yet to see evidence that Twitter deserves a multibillion-dollar market cap.

In addition, most of tech's recent IPOs have been relatively small fry. Business intelligence specialist Qlik Technologies (Nasdaq: QLIK) took in $112 million in its July IPO, and online Indian travel company MakeMyTrip (Nasdaq: MMYT) received $70 million in August.

Regardless, there is evidence of a shift toward mobile and localized content and commerce on the web -- the sort that Twitter can deliver -- powered in large part by location-aware smartphones such as Research In Motion's (Nasdaq: RIMM) BlackBerry.

It'd be a big-money opportunity. But don't take my word for it; look at the numbers. Sales of BlackBerry handsets and services alone account for more than $16 billion annually. Mixing in iPhone and Android handsets and services would multiply that total.

Can Costolo get Twitter surfing this multibillion-dollar wave? Williams seems to think so, and so do I. Do you agree? Share your thoughts in the comments box below.