jackkistler said:
I imagine there are a lot of people activating and doing clean installs of Win10, then having to reload all of their games. With Steam, with their huge catalog of games, this can put a huge load on their servers during the weeks just after the Win10 release. If my supposition is correct, this should settle down in a while.
The fact that I never thought of that. Derp. You're most likely correct. So far I haven't had the problem again. So that's good.