One of my clients had a huge website/blog with pages and pages of content. This website was put in the Google "Sandbox", meaning that his page rank went to 0 where it was a page rank of 3.
How could this happen? After much study, I found that this lawyer's website had virtually no incoming links (ie other sites referencing parts of the lawyer's website). There was about 1000 pages of content with only 20 incoming links. Google must have thought that this was a "spam" type site. We immediately posted his site on some free law firm directories, his local bar association, and places like Findlaw. It took a few months, but his site got back to a Google page rank of 3.
Lesson learned, don't forget incoming links. (caution, only link with reputable sites that have similar "legal" themes)