This afternoon Steam has been having a bit of trouble staying up in several areas. In Europe East servers especially, with a high number of players searching for the term - as you likely know already. There aren’t an inordinate amount of people on Steam at the moment - nearly 5.5 million - and Steam database clients are currently set to "Normal" mode.
Team Fortress 2 servers experienced an extra-high load this morning and are currently in the process of reloading now. The Team Fortress 2 Game Coordinator is currently set to "Launching" mode right this minute.
UPDATE: Europe East is now experiencing "High Load" as well, while Europe West has gone back to a "Low Load" signature.
You’ll notice a bit of a blip around 2 hours ago, while service appears to be back on track for this afternoon. If you’re having trouble accessing Steam today, we recommend restarting your computer, restarting your modem, or twiddling your thumbs rapidly.
UPDATE 2: Steam appears to be fully restored - if you're still having trouble, consider the following words of wisdom: