Skype still uses OSS under linux.

Since it's a new company where the software got developed while ALSA was available, I have to question why they released a "public" linux version that still does not offer ALSA, even after every second post in their linux forums asked for it.

Then there's also the possibility that, had their software been open-sourced, someone would have already added ALSA functionality to it; But that's for a different thread.