[ffsanotheracct]

Sure, if they don't want to be indexed by search engines. And if they do, suddenly browsers are going to have user agents that look a lot like search engines. And failing that, anyone who tries this had best pray they're the ONLY source of that content, because otherwise their traffic will dry up like a piece of chewed up gum in the Mojave (and even if they ARE the only source, if it's worth anything at all, it'll be quoted whole and reposted all over so it can be read by people unwilling to put up with any of that).