As a disinterested observer, I can say two things:<p>1) They're pretty<p>2) They piss me off<p>These sites scream style over substance. I can't think of an Alexa top 500 site that uses this kind of design. The only one I frequent would be Grooveshark, and their design is highly functional.<p>Between facebook, gmail, reddit, HN, and the various blogs and news sites I visit, 98% of my time online is spent on sites that look nothing like these. Even Hipmunk, while very web 2.0, is completely function-focused. These sites seem like they're pretty for the sake of being pretty, and I couldn't for the life of me say what a single one of them actually does.