Einmal:

"Steam has NOT been hacked.
This is a server issue, as is fairly obvious.
This problem is due to how steam is caching pages. Going to your own page, and viewing it loads it into the cache. The Steam servers are showing cached pages created by other users to all users, allowing people to view pages "created" by other users steam accounts. Not doing that means it's not going to be accessible or rerouted to other people. Do NOT go into any of your account detail pages (payment history, account info, etc) and you'll be fine."

Und dann :

"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."

Frohe Weihnachten xD