The company is listing four open positions with the word "monetization" in their title, as well as several others related to business development.

The job listings suggest Twitter is paying increased attention to ways in which it can rev up its revenue engine, now that it has evolved from a curio for techies to a mainstream communication tool used by millions of regular folks, as well as celebrities and large companies.

While the San Francisco phenom has been generously funded by its backers, industry observers have insistently questioned whether the company will be able to establish a sustainable business model. If not, speculation has been that it could be acquired by the likes of Google or Microsoft.

Twitter lets its users post text messages of up to 140 characters, a deceptively minimalistic feature that millions of individuals and thousands of organizations and external developers have found myriad ways to leverage.

The four "monetization" jobs Twitter has open are: ; ; ; and .