From ICT4D Wiki

comScore maintains massive proprietary databases that provide a continuous, real-time measurement of the myriad ways in which the Internet is used and the wide variety of activities that are occurring online. Mission-critical information relating to both offline and online activities is collected through comScore's innovative use of the Internet as a timely and powerful data collection medium.

Not that they really publish reports in depth reports — not, at least, to non-costumers ;) — but their press room might be useful to get some interesting news.