As for the announcement, here (lightly edited) is what's posted on the Z-Man Games news page:
This time, Christian Marcussen gives us a civilization game, with his own personal twist! Contrarily to other civilization games, in Clash of Cultures you do not portray any given culture, nor does it depict historical events. History is not influencing the game; you are writing your own story, building your own civilization. You can clearly see this in the sketch for our box top [posted above right] that was designed by Chris Quilliams (Merchants & Marauders); different societies that didn't exist in the same time period can coexist in Clash of Cultures.
You will discover, in the weeks to come, that there are multiple ways to play Clash of Cultures. Each player will want to concentrate on different aspects than the others, which will change the dynamic of the game every time!
More to come about Clash of Cultures next week!