A fresh analysis of the world s most-visited websites shows that vulnerable software, too much active content and large amounts of code execution open visitors to a raft of potential dangers. A full 42 percent of the Alexa Top 100,000 sites globally were deemed risky because they either used unpatched server software known to be vulnerable; or, the site had served malware/launched attacks, or suffered a security breach in the past year. The more active code a site downloads, the greater the risk.
Source: https://threatpost.com/threatlist-almost-half-of-the-worlds-top-websites-deemed-risky/136636/