"In part due to its quantifiable nature and to technological advances that permit better tracking of citations within books and journal articles, the number of times a particular article or publication is cited has become a common method of assessing the article’s impact on furthering knowledge in the field. Additionally, researchers use citation rates as a means of identifying which among a long list of articles may be the most useful to their research, as well as to map the development of an idea over time. In many cases, citation rates for faculty research play a role in university rankings." Source: AASCB website
From Online Databases: The Power of Citation Searching
"The power of citation searching lies in the capacity to take a seminal article and uncover who the author was influenced by (who was cited) and go forward in time to discover how that seminal research affected newer works (who is citing it). ISI (a Thomson business, formerly Institute for Scientific Information) has allowed such techniques to be used by serious searchers for years by providing the means of searching for known articles or authors in the "cited reference" field of ISI's citation indexes."...
Anyone who works in academia is familiar with another common use: professors who want to measure the impact of their work want to know how many (and which) researchers are referring to their articles, knowledge of which may bear on promotion and tenure decisions.
Impact, as measured by number of cites, is also extended to journals. (ISI Journal Citation Reports show which journals receive the most citations on the average per article, and, rightly or wrongly, authors in some countries are paid bonuses for publishing in high-impact journals.) For academic disciplines, ISI Essential Science Indicators provides rankings of nations, individuals, or journals or universities themselves (universities are ranked according to the collective citations to their faculties).
ISI's Rodney Yancey, manager of corporate communications, also suggests that researchers use citation searching to "track the work of a research colleague or noted authority; verify the accuracy of cited references; identify the sources of information that competitors worldwide are consulting for their research; and construct an objective history of a field of study, significant invention or discovery."
He further explains that citation indexing "exploits the formal linkages between papers established by the authors themselves. Citation searching offers the unique capability of finding new, unknown information, based on older, known information. Going forward in time, a user can take a seminal paper and discover what influenced that work and then trace that idea forward to see its impact."