Many marketers fall into the trap of believing that most qualities Google's bots look for in a website are objective and therefore don't have as much to do with visual design. It's true that most of what the search engine looks for has to do with quantifiable factors, such as how many keywords are present and how frequently updates are made to a particular news feed.
However, the latest update from Google's search team has been specifically created with design and readability in mind. One trick that some devious online marketing firms played on search users was to put large ads on landing pages that required people to scroll down for the pertinent content that brought them to a website in the first place.
Google's algorithms, which have become sophisticated enough to be able to screen for this sort of thing, have been modified to penalize web pages that engage in this sort of practice. This is simply another instance of the search engine giant striving to put quality content over promotional opportunities. This ultimately lends credence to the idea that search engine optimization needs to be a subtle form of marketing rather than a blatant attempt to put advertisements in front of consumers.