In a way, though we are conditioned not to expect accuracy online, it is even more important there than elsewhere. When you are communicating face to face, you get all the non-verbal cues like facial expression and tone of voice to help get your message across. When you're on the phone, you lose the visual, but you still get the auditory undertones. When you're online, communicating only in text, you only get that text to convey your message. If your message is subtle or complex, face to face you might get away with some vagueness and people will still understand you. Online, however, you are already at a disadvantage. If your attitude is "it's just the internet, nobody takes it seriously" then you will almost always be misunderstood. When people misunderstand you online, two things can happen. One, you could find yourself engaged in a flame war over a perceived slight or some other problem. Two, you could just be ignored, mentally filed under the heading of "that one who doesn't make sense online" and people won't bother reading what you have to say, because it's just too confusing.
Mokalus of Borg
PS - That's why accuracy matters online. If you ignore it, the world will end up ignoring you.
PPS - And in an attention economy, being ignored is exactly like going broke.