Hm. I was away today, and coming back I checked the expected GOG announcement:
https://secure.gog.com/news/cd_projekt_red_gogcom_summer_conference
It says "Watch it right here!". However all is there is just a gray empty area... Can anyone actually see the supposed video?
Witcher 3 trailer was working at least. Great to see other witchers returning, as well as Yennefer and Ciri being in the game. I won't preorder it however, until CDPR will confirm a Linux version.
UPDATE: I figured the problem (watching the presentation now). I was using the HTTPS page with HTTPS everywhere enabled, and GOG used Livestream video (with Flash). That must have choked somehow. Disabling HTTPS everywhere and using regular page worked. GOG should fix this. Unveiling new projects while failing at handling simple HTTPS pages looks a bit unprofessional.
OK, so they talked about the optional client, but didn't say anything whether it will be open source or not. I hope they won't blow it and won't make it closed like Steam does.