Some frequently asked questions:
– No, Steam is not hacked
– Creditcard info and phone numbers are, as required by law, censored and not visible to users
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.
25 Dec 2015, 23:16 GMT: The issue now appears to have been resolved, and the Steam Store is back online.