Am I right in thinking this doesn't actually mean you can play your games when you are off the internet? 

My internet has been off for about 24hrs, I wanted to play my games but they said they needed Steam to be played.

I started off Steam but it wouldn't start without the Internet, I tried "offline mode" but that said it's not allowed to start without an internet connection...doesn't that defeat the idea of it being an "Offline Mode"? Or am I missing something?

As far as I know (not much of a PC gamer), you have to connect online just to log in to Steam for authentication, but you can then play offline for as long as you want. It stops it from eating up your bandwidth and such.

you need to be online first then you can switch to offline modus. It doesnt work if you cant connect to steam first.
after that most games will work offline even if you dont have inet.

after that you wont have to login again for a big period of time. but it sucks that you cant switch to offline mode without being online first :(

Blerh sad times. Thanks folks

that's why I always have pdanet on my smart phone ready >.>; at least then I can switch to offline mode.

except if there are steam login problems like a few weeks ago for germans who couldnt log in for 2 days :(

yeah, I feel for the non US people on that one, I live not that far away from Valve so Steam is like, super good here lol.

But you've been online before this, haven't you? Why doesn't it work?

If I turn off my wireless it still lets me start SimCity 4 at least... it tries to connect to Steam but can't, then asks if I want to start in offline mode.

Have you played this particular game before? Maybe the first time you play each game you have to be online.

Steam's offline mode is kinda shit, sometimes it will work others it won't, seems pretty random TBH. People have been asking them to fix it for years but it's Valve so the devs work on what they want so features like that get ignored.