Libraries and authors have been trying to determine the validity and accuracy of usage statistics.
Usage data was originally measuring shelving statistics of print volumes, and now in the digital environment can measure the usage of individual component parts (ie. the specific journal article within a journal title, a book chapter in a volume, etc.)
Newer based products are at the article level metric and are being explored by different producers.
The big picture is assumed by vendor-generated data, such as with COUNTER Online Metrics, which also provides UsageFactor, Publisher and Institutional Repository Usage Statistics (PIRUS2), and the embedding of PageRank into Google's metrics, and the Y-Factor, a morphing of impact factor and PageRank.
Co-citation tools offer visualizations and clusters between authors to determine relationships and how their scholarship impacts each other. The information science literature explains the significance of these networks and some software tools illustrate the formation of these clusters.
One of the best tables that compares many of the current traditional and alternative metrics is part of a LibGuide created at the University of Utrecht.
Many libraries are trying to draw readers to their institutional repositories and content deposited there is usually crawled by search engines. In addition to organizing content and elements retrieved from other traditional and secondary sources, it has become useful for researchers to organize and customize their retrieved references. New products are being created, tested and released that aid this effort.