[quote=@Odin]
<Snipped quote by Grim>

There is no reason [i]not[/i] to include a history - it's the personality that's highly unneeded. Whether or not you believe a history is irrelevant IC is one thing but it provides good hooks for other peoples' characters to hook into if invited to/if they are good roleplayers that know character interactivity drives a roleplay forwards. History motivates why a character acts a certain why if properly written (which I'll admit mostly isn't the case on RPG, but ideally it does) and substitutes a personality section entirely.

Failure to include [i]some[/i] form of history is only acceptable if the character is literally fresh out of the womb. Otherwise your character will resemble something close to a walled off section in the RP - floating on its' own with no connectivity to the roleplaying world around him/her and you might be better off writing a book or making your own solo RP. 

[@BrokenPromise] Fair enough, length can be irrelevant at most times. Essential is subjective I think - imho, history should always be essential to tie a character to the world. I find that saying 'history will be revealed IC' is a thing that poor writers usually do when they can't be arsed to write a history or something. Leaving it completely out is, as described above, also just poor connection to the world around you. Short or long, there should be some kind of idea of what this character has done and gone through to motivate thoughts, actions, etcetera. It forms your area of reference - seems to be a critical part of a good character sheet to me.

EDIT: inb4 'it's in my head and that's what counts' yeah but if it's in your head then you might as well write it down.
[/quote]

I disagree in some ways,
I think that personality is important, it may not need to be included in the CS but I believe that the player should have an idea of the personality to keep it constant.