I was thinking that when buying books, people often take notice of recommendations from Amazon or random sites through Google or discussion sites like this one, but a recommendation from someone I know or interact with is preferable when I can get it. And it's not necessarily preferable because of a higher quality recommendation: a recommendation from a person implies some degree of meaningful interaction with them that contributes to an overall sense of.. meaningful-ness even if the book turns out to be awful. Plus if it turns out to be awful, I can discuss it with that person further and possibly get a better recommendation. Plus whether or not it's awful, I can talk with them about it after reading it for additional meaningful interaction.

I think that kind of loss of meaningful interaction is a pretty small thing, but it can add up over time and have a greater impact with high usage of services like Google that automate things that previously generally involved more human interaction. And sure, no one's forcing anyone to use Google or Amazon instead of talking to people, but it's a fairly subtle opportunity cost that comes with using those services. And those kinds of services are convenient and useful enough that it's quite easy to make a habit of using them, and habits aren't easy to change.