Personally, I think they're playing with L4D2 because it's more stable. TF2 is getting content updates every few weeks, while L4D2 is still new but relatively stable. Maybe just for the sensitive stage where they want to make sure it works just fine (with an acceptable framerate, which is probably the hard part) they want a game that doesn't push new hats to the client every other week. Once everything is smooth, I imagine it's trivial to move the rest of the Source engine games over.
Someone whose only training was using a mouse in a FPS, sorry, I don't think they'll be particularly good at it.
At least they'll be better than the ones using console controllers.
Early after I made my Slashdot account I had adblock on but didn't pay it any mind, and then I saw the "thanks to you contributing positively to this board, you are eligible to turn off ads"
I felt it was such an honorable and honest system that I disabled adblock for Slashdot and didn't opt-out of the ads. It also made me disable it for other sites I appreciate, like Hulu or even Google.com. Reddit has a "Thank you for not using AdBlock" graphic in place of an ad sometimes. I think it's what Google was saying some time ago: adblockers aren't ruining free websites, people will eventually use them to block out annoying or undesirable ads while choosing to support the websites they would like to support.
Not that I'm saying this behavior is in the majority, but it might grow with the usage of AdBlockers.
Not only that, but there are OTHER insomniacs in OTHER time zones, meaning interaction can depend more on "when they happen to be awake" and not "what time they're usually up"
the first thing I noticed is that XMPP doesn't keep losing connection and trying to login.
though I don't think it might be an issue to everyone, but on the facebook chat plugin it would query who is online and who isn't at time intervals, resulting in mass signings/signouts at once depending on the time of day + size of friends list. I'm not sure if the xmpp system is any better but I assume it will be more real-time.