UPDATE 2014-09: KakaoTalk have now launched a full-fledged English blog. The link below is still active though, and seems to focus more on the "fun/social" aspects of the service, while the new blog is more about features/services.
main Korean-language blog here, with an RSS link here. It has lots of information on the company and the technical side of Kakao services like KakaoTalk and KakaoStory.
But if you want English-language information, which usually concentrates on new feature releases and promotions, their Facebook page is your best source of information. So, since they don't really have an active English-langauge blog, you can just subscribe to their Facebook page feed in your RSS reader, at this link:
This is a good source of information, for example, about the new Mac version of KakaoTalk for the desktop.