Johnson, Kaye, Bichard, and Wong (2007) surveyed 1,399 internet users online during a four-week period surrounding the 2004 presidential election day (October 19 to November 16). The study applied uses and gratification theory to study credibility, which purportedly had not been widely used by credibility researchers. Amongst the hypotheses tested were whether motivations for using blogs and whether reliance on blogs for political information significantly predicted perception of blog credibility. Motivations were measured in terms of: 1) information seeking/media checking (searching about current issues), 2) convenience (using blogs because it’s more convenient and easier to reach than traditional media or other online sources), 3) personal fulfillment (fulfilling emotional needs and gathering information to use in discussion with others), 4) political surveillance, and 5) social surveillance (learning about others’ opinions).

Credibility was measured in terms of believability, fairness, accuracy, in-depth, and a combined index. After controlling for political and demographic variables, reliance on blogs was found to be a stronger predictor than motivation; and political information seeking was the strongest motivational predictor. In addition, participants found blogs to be higher in credibility for depth of information than traditional media or other online sources (p <.001, two tailed), albeit lowest in credibility for fairness of information. You can read the full article from this 2007 Journal of Computer Mediated Communication here.