This is big big news for the wordpress theme community. Ian has been a leader in the community for quite some time and is responsible for the development of thematic, one of the best wordpress theme frameworks around. (Slight segway: learn more about theme frameworks.)
Having played around extensively with thematic, I can safely say Ian is a very talented guy who is undoubtedly going to be a massive contributor to the core wordpress project going forward.
The other excellent piece of news that comes with this announcement is that Ian has released his previously commercial thematic child themes as free themes!
You can check theme out below:
It would appear that thematic is also going to become a key resource for Automattic in the future – from Ian:
ThemeShaper will become a public-facing blog for the Theme Team now assembling at Automattic. A place where we can help provide the best possible experience for everyone involved in WordPress theming; from the noobiest of beginners to the most powerful of WordPress wizards.
This is really exciting stuff from Ian and Automattic. One might speculate as to what Automattic are planning. Could it be that they are going to start producing a lot more wordpress themes of their own to a standard that the premium theme providers are providing at the moment? Or will it be a more of a learning/teaching/support resource? Time will tell.
For now we wish Ian the very best of luck in his new role with Automattic!