Brad Plumer, responding to a Clark Williams-Derry philippic against the white pages, says:
In the age of Google and unlisted cell phones, paper phone directories are being used less and less: One Gallup survey found that, in 2008, just 11 percent of households actually relied on them. Yet the vast majority of states still have laws mandating their delivery.
True enough. But when was the last time you used Google to look up a phone number? Sure, I do it occasionally, but not all that often, really. Rather, my guess is that the decline of the white pages is due mostly to ubiquitous auto dialers, email, and social media. Electronic phone books allow you to easily store hundreds of numbers and always have them at your fingertips. Email means that you have an alternate way of contacting someone you don't know well (and also an alternate means of asking for a phone number if you want to talk). And social media means that you have easy access to a much wider circle of acquaintances than you used to. I'd guess that these are the real reasons that so few people use the white pages anymore.
But who cares? Either way, it's probably time to get rid of them.