An implication of this is that old sites tend to disappear (either into obscurity or by being taken down) because Google penalizes them in search rankings. The author of this search engine says, however:
> If a webpage has been around for a long time, then odds are it has fundamental redeeming quality that has motivated keeping it around all for that time.
I don't know that I agree 100% with this (there was lots of crap on the "old" web too), but it makes a certain amount of sense.