The scholarly literature is a vast store of formalized human knowledge, interconnected by citations between publications.
Looking at these citations is one way to measure the influence of scholarly research. Metrics like h-index—prominently displayed by services such as Google Scholar—measure influence by counting citations. But with more complete data about these citations getting better and more accessible every day, we can do better.
Scholar.eigenfactor.org gives you tools to use citations to measure and visualize the influence of collections of papers. These collections can represent, for example, individual scholars, or journals, academic departments, or fields of study.