PLoS Article Level Metrics

From the PLoS website: 

The Public Library of Science (PLoS) is the first publisher to place transparent and  comprehensive information about the usage and reach of published articles onto the articles themselves, so that the entire academic community can assess their value.  We call these measures for evaluating articles ‘Article-Level Metrics‘, and they are distinct from the journal-level measures of research quality that have traditionally been made available until now.

So far the available data includes…

• Article usage statistics - HTML pageviews, PDF downloads  and XML downloads
• Citations from the scholarly literature – currently from PubMed Central, Scopus and CrossRef
• Social bookmarks - currently from CiteULike and Connotea
• Comments – left by readers of each article
• Notes – left by readers of each article
• Blog posts – aggregated from Postgenomic, Nature Blogs, and Bloglines
• Ratings – left by readers of each article