Whether anyone would like to admit it completely or not, because of the need to perform in Google’s search results, the search engine, at least indirectly, dictates how websites should be built. Fun things like Flash were vilified because of the havoc it caused in being properly seen by Google. There are probably many more examples that you folks who build sites could come up with as well (feel free to share them in the comments if you feel the need to vent).
Today (maybe to clear up some concerns?), Google has issued The Google HTML and CSS Style Guide. From the post on the Webmaster Central blog we get













