Cited by Information tells you how often individual articles or publications have been referred to by other articles/publications. This citing number is a convenient example of their usefulness, or their authority by their peers.
Note older articles will naturally have more cites than newer ones, as they have had longer times to acrue more. A recent article with a good body of cites will be an indicator of quality material. The best articles, that have been published long enough to gain cites, will have thousands of citations.
