[Update]: The Steam store is now back up, as of 11:00 a.m. PST. As predicted, Valve seems to be content pretending this never happened, as there has been no announcement whatsoever since Steam originally went down earlier this morning.
[Original Story]: Well, it appears the Steam Winter Sale may have been too much for Valve to handle, as Steam inexplicably went down this morning for several hours across the globe.
As of writing this, steampowered.com, as well as the desktop app for Steam is still not functioning. While there has been no confirmation from Valve as to the cause of this disruption, Valve also hasn't even publicly noted that this disruption is happening, so your guess is as good as mine.
Of course, reasons could range anywhere from a DDoS attack to some unscheduled maintenance. My guess is that we won't know even when it does get resolved. Valve will just quietly resolve the issue and pretend it never happened.
While we wait for some sort of post on social media to let us know what's going on, our only hope is to mindlessly refresh isitdownrightnow.com or the store page itself to see if maybe, just maybe, we can get our hands on those unbelievable deals once more.
GameRevolution will have more as this story develops.