Citation counts show the number of times an article is cited by other researchers. It is one way to measure the impact of a scholar's work. Several databases keep track of citation counts within that database.
The "Cited by" link show many articles have made a citation or reference to this article. If you click on the link you can see a list of the articles.
Click the "Citing Articles" link on the right side of the screen to see a list of the articles that have cited your article.
You can also search for citation counts in Google Scholar. Click the "Cited by" link to see a list of the articles that have cited your article.