Who has written key articles in your field? Citation indexes track the references in published papers so that you can see (by the number of citations to a paper) who has written key articles.
Have you found a brilliant article and are wondering if other researchers are working on the same topic? Citation searching also shows you who has used a individual article in his/her own work and is therefore building on the earlier work.
Who has cited a reference? Who is citing your articles? How many times have you been cited?
For detailed guidance on which databases to use see our guide on How to Find Citations.
Web of Science: Citation Report (YouTube)