If you were to restart your Steam account, you'd notice that your copy of Left 4 Dead 2 would start updating. This is to add in the beta for a new campaign, Cold Stream. It has a few bugs, but that's why God gave us betas. Wow, that's such a succinct news story I need to add another.
If you were to restart your Steam account, you'd notice that it would have updated to change its voice chat technology. As anyone who's ever used Steam Voice will know, it wasn't exactly as good as it could have been. It's now been replaced with SILK, an audio codec developed by the Skype peeps, with what I like to call a "dynamic bit rate protocol", meaning it can vary its bandwidth up to 30kbps (twice as much as Steam Voice would use.) Valve adds that the voice chat connectivity and reliability has also been improved, which is mighty fine news as we were increasingly finding ourselves opting for using non-Steam chat when playing together. Isn't that all smashing?