The online community of people who write blogs, known as bloggers, whose principal motivations are self expression and sharing of expertise and personal experiences. The term blogosphere was coined by Brad Graham in 1999 and propagated more widely by William Quirk. The blogosphere is constantly expanding as blogging has become ubiquitous, effective, and authentic; the blogosphere is important to both opinion forming and promotion of expertise. Inhabitants of the blogosphere universe are both amateur and professional. A recent element of the blogosphere's expansion is the use of social media, such as Twitter to promote individual blogs, particularly by professional bloggers.