Co-citation is a Search Engine Optimization (SEO) tool used to establish similarities between items.
For example, if two different sources are sited by a third source, the first two sources are "co-cited" and therefore similar, or at least related in some way.
Sean B. Eom has written: 'Student satisfaction and learning outcomes in e-learning' -- subject(s): Distance education, Computer-assisted instruction, Psychology of Learning 'Author cocitation analysis' -- subject(s): Bibliography, Bibliometrics, Data processing, Databases, Multivariate analysis, Research, Statistical methods 'Decision Support Systems Research (1970-1999)'