Isn't it superfluous or just plain lazy to write to someone that you don't know something. You know, like I don't know who or what Kaiser Soze is or which is the 10th closest star from the earth, or just where do we get hing (asafoetida) from?
Or when someone writes "You, noob!" on chat, you can't just reply, "I don't know what you mean". That will make you more of a noob
You know, if you are writing, then you are either on email or chat (who writes on the paper anyway, apart from the devil printers) And in that case, you can easily find out the information for yourself - google is at your fingertips. So, why can't you not know?
It doesn't matter that you didn't know stuff, and it doesn't matter that you don't know stuff when you talk to real people. But when you write, you are all-knowing. You can be a wise erudite info-whore.
NB - Does excessive pursuit of knowledge make you a wikipedo-phile?