My Steam Account isn't linking, I'll click the Link button, get brought to a Steam Login page.  When I login there, it brings me back, it still doesn't show as linked.  Sometimes, I see the bar start to fill up, but stops 1/3 of the way.

It finally did link, please disregard

I'm glad it did for you but it still han't for me :(

Looking at post times, I guess we have to stare at an unresponsive page for a full hour before the two sites sync?

Man, really? After it didn't synch for half an hour I tried reloading it, assuming that something got stuck, and then it didn't work again. Was I just supposed to wait some more?

Same here, I've tried logging in on different browses and stuff, but opening chrome's console (f12) shows these errors: 

Same for me. I am logged in to Steam on their Website on another Tab, but it doesn's work.

It takes some time, I couldn't do it before one day until just recently the next day it worked. pretty sure they did say something in the news saying to wait a bit because of the servers were having high volume at certain times.