Sometimes a quantitative difference becomes a qualitative difference. For example, motorcycles are just faster horses (in some ways worse, like for off-roading), but you could hardly argue they are the same thing. I would argue that google is substantially more useful than altavista, or dogpile, ever were.

And ultimately Altavista and Dogpile are irrelevant, because neither existed just a few years before Google. Web search is revolutionary; search engines before Google were just halting steps on the way. That is, the contention isn't that Google revolutionized web search, but that web search revolutionized the world.

An extreme change in accuracy and speed might as well be...a revolution.