Perhaps the best way to understand the potential impact of Google upon content management is to remember the internet before Google. Back then, search engines relied upon html meta tags and text indexing. Because those who should have supplied the meta tags usually forgot and those who remembered usually lied [in an attempt to boost their search position], meta tags became almost useless. Consequently, successful searching depended upon one’s ability to select key words and form boolean queries.
Unfortunately, full text search is quite inefficient in determining the intent of any given piece of content. Yahoo responded by starting to read the web in order to categorize it. The genius of Google was in realizing that they could leverage the work of others who were reading the web and recording their understanding in the form of hyperlinks.
In principle, content management systems could leverage that same insight to improve their search. However, that also requires that the users read the content and provide a record of their understanding - in other words, a k-blog.