For example, if a user in Kalamazoo, Michigan happens to have a DNS server in San Francisco, that server might pass the request off to the nearest content network – also in San Francisco. That means having to push data from SF to Kalamazoo, which is obviously a longer trip than necessary. If the DNS server knew just where its requests originated, geographically, it could make smarter choices about content providers: that Kalamazoo user, say, might instead use a Detroit content network.
Not everyone's on board with the plan; Akamai isn't impressed, saying there are better ways to speed up the net. But you'll surely earn geek cred for bringing up DNS optimization at your next cocktail party.