13. A computer-readable storage medium containing instructions for controlling a computer system to adjust the influence of a first author on a topic, by a method comprising: identifying articles posted by the first author on the topic during a current period and an earlier period; identifying other authors that cited or posted articles on the topic during the current or earlier periods; for each of the other authors, determining the authority of each of the other authors based on whether the other authors cite during the current period an identified article posted by the first author; and adjusting the influence of the first author on the topic based at least upon the determined authority of each of the other authors that cites during the current period an identified article posted by the first author, and whether the first author published an article during the earlier period; before adjusting the influence for the current period of the first author's post of the identified article, initializing the influence for the current time period based on the influence for the latest earlier period; and adjusting the influence to reflect an increase in authority if the first author has published on the topic during the current period; wherein adjusting the influence of the first author on the topic based at least upon whether the other authors cite during the current period an identified article posted by the first author for each author identified as the other authors includes increasing the influence if the other authors cite during the current period the identified article and decreasing the influence if the other authors do not cite the identified article during the current period.
13. A computer-readable storage medium containing instructions for controlling a computer system to adjust the influence of a first author on a topic, by a method comprising: identifying articles posted by the first author on the topic during a current period and an earlier period; identifying other authors that cited or posted articles on the topic during the current or earlier periods; for each of the other authors, determining the authority of each of the other authors based on whether the other authors cite during the current period an identified article posted by the first author; and adjusting the influence of the first author on the topic based at least upon the determined authority of each of the other authors that cites during the current period an identified article posted by the first author, and whether the first author published an article during the earlier period; before adjusting the influence for the current period of the first author's post of the identified article, initializing the influence for the current time period based on the influence for the latest earlier period; and adjusting the influence to reflect an increase in authority if the first author has published on the topic during the current period; wherein adjusting the influence of the first author on the topic based at least upon whether the other authors cite during the current period an identified article posted by the first author for each author identified as the other authors includes increasing the influence if the other authors cite during the current period the identified article and decreasing the influence if the other authors do not cite the identified article during the current period. 16. The computer-readable storage medium of claim 13 wherein determining whether an author cited a post includes identifying trackbacks to the post.