Source: Shutterstock Twitter continues to explore and appraise long-term revenue models. For the time being, Twitter’s primary focus is to build and nurture a thriving and indispensable community.  Equally critical is the company’s ability to steer engineering and marketing efforts towards developers to empower them to extend, evolve, and enhance the overall Twitter experience for the vast landscape of discerning users as well as those new members who have yet to realize its potential. In July 2009, we were introduced…