The content of the tabs shows an interesting progression as well. The Apple logo, Store, and Support tabs are a common thread throughout with Search appearing surprisingly late in the game in 2007. These unchanging outer items are like bookends around the changing world of Apple over time.
For the first seven years, the inner tabs mainly focused on software (QuickTime, Mac OS X, iTunes) and different incarnations of online services (iReview, iCard, iTools which became .Mac). The first hardware to appear on a tab was iPod, but it had to share a tab with iTunes for almost seven years before getting a tab of its own.