Someone claiming to be affiliated with Anonymous compromised a private web hosting service last week, taking down more than 10,000 sites on the highly encrypted “dark web,” security researchers said. The hacker or hackers broke into the hidden web hosting service Freedom Hosting II, claiming to have harvested all of the sites’ files and its database, totaling almost 80 gigabytes of material, they said in a message appearing on the screens of users trying to access the sites.