After NEC, in 2004 it was hosted as CiteSeer.IST on the World Wide Web at the College of Information Sciences and Technology, The Pennsylvania State University, and had over 700,000 documents. For enhanced access, performance and research, similar versions of CiteSeer were supported at universities such as the Massachusetts Institute of Technology, University of Zürich and the National University of Singapore. However, these versions of CiteSeer proved difficult to maintain and are no longer available. Because CiteSeer only indexes freely available papers on the web and does not have access to publisher metadata, it returns fewer citation counts than sites, such as Google Scholar, that have publisher metadata.