Google just released their Malware Distribution Transparency Report, sharing the amount of sites compromised or distributing malware detected by their systems (Safe Browsing program).
Google’s Safe Browsing program started in 2006 and since has become one of the most useful blacklists to detect and report on compromised sites. They flag around 10,000 different sites per day, which are being used for over 1 billion browser (Chrome, Firefox And Safari) users.
What is really scary from their report is the amount of legitimate compromised sites hosting malware compared to sites developed by the bad guys for malicious purposes. For example, in the first week of Jun/2013, 37,000 legitimate sites were compromised to host malware. At the same time, they only identified around 4,000 sites that were developed for the unique purpose of infecting people.