You should have checked "Remember my credentials offline, or wait a few hours untill the problem is fixed. Lan is still working. Online Multiplayer won't. Non-Valve games are unlimitedly downloadable but usualy do not even require Steam. Steam is just the download client basicaly.What if they go offline?
If anyone, Valve, next to id software maybe, has a record of always patching even 10 year old stuff. Usualy you'll eventually may even get some games for free (like Blue Shift). When Steam/Valve goes bankrupt/down, standalone patches (aka legal craks) will be supplied. You should have made a backup copy of your game after (unlimited time are granted for this, same as downloads; ) activation. There is a built-in, not-hidden GUI wizzard for this in Steam. These cracks will decrypt the encryption and the game is now free to be copied to whatever media you like, as many times as you like, without any copyright. So when Steam closes down, you'll end up having better softwareWhat if the game simply stops being "supported" by the DRM? Will they then release that control over to you? Etc.
Pay money to Valve; they will makje Linux so much more popular and mainstream accepted that eventually more FLOSS will be used (aka non-Microsoft) and so more bug reports, more possible contributors to FLOSS, more pressure on manufacturors to make their tech work with Linux (or die)...Of course, any of you are free to pay for even a single ride on the software roller coaster, that's fine, and I myself do so sometimes, but I'd prefer to have the opportunity to invest in open source programs instead especially when I know my monetary support won't be misused.