Valve had made or received, for lack of a better word, a major fuck up where everyone within a window of a few hours have been able to view account information of random Steam users. Usernames, email address, profiles info, and possibly home address.
Another few hours later valve issued a state regarding what happened. From what they’re saying, no one hacked Steam and that it was just a major screw up on Valve’s end.
“Steam is back up and running without any known issues. As a result of a configuration change earlier today, a caching issue allowed some users to randomly see pages generated for other users for a period of less than an hour. This issue has since been resolved. We believe no unauthorized actions were allowed on accounts beyond the viewing of cached page information and no additional action is required by users.”