Sometimes it's an improvement and sometimes it's an over-commercialized pile of crap. Whatever it is, it's usually a reinvention.
Blogging + Technocrati + A feed reader = Usenet
OSX - A proper app. security layer = Vista
iGoogle = Windows Live + Interesting Feeds - Commercial Feeds
Ubuntu - An evil Wallpapers + Daily Bible verses = Christian Ubuntu
Jews - religion = Muslims - religion
Danish food - salt - grease = vacuum