"The Content Rules" was written by CC Chapman last year, and I was wondering if the book was still relivent in 2012, or if the ideas in it are dated. I started reading it in 2011, didn't finish it, but now I feel like I might have a need to read it again which is why I ask.
Usability and content writing principles have been around since the dawn of the internet, and all them still hold true. I would strongly suggest doing some usability research in conjunction with your content research.
Web writing can be a full-time job, there are a lot of rules to follow. I personally haven't read "The Content Rules", however it would likely still apply. I've used content writing research done in 2001 - the internet hasn't changed much in how we use it. You still have text on a page, and you still stare at a screen and read the text.