Comscore - "Comscore is a trusted partner for planning, transacting and evaluating media across platforms. With transformative data science and vast audience insights across digital, linear TV, over-the-top (OTT) and theatrical viewership, we are a powerful third-party source for reliable measurement of cross-platform audiences." Provides infographics and charts.
Nielsen State of the Media Reports - "Nielsen is a global measurement and data analytics company that provides the most complete and trusted view available of consumers and markets worldwide. Our approach marries proprietary Nielsen data with other data sources to help clients around the world understand what's happening now, what's happening next, and how to best act on this knowledge." Access reports and ratings.
Social Computing Data Repository at Arizona State University - Social Computing Data Repository hosts data from a collection of many different social media sites, most of which have blogging capacity. Some of the prominent social media sites included in this repository are BlogCatalog, Twitter, MyBlogLog, Digg, StumbleUpon, del.icio.us, MySpace, LiveJournal, The Unofficial Apple Weblog (TUAW), Reddit, etc.
StatCounter Social Media Stats - Stats are based on aggregate data collected by StatCounter on a sample exceeding 10 billion pageviews per month collected from across the StatCounter network of more than 2 million websites.