Beginning writers (and noders) are often told to "write what they know." On the surface, this admonition seems wise, as it discourages novices from making stuff up or blathering endlessly on topics about which they know nothing. After all, there's nothing worse than an article that begins "I don't know much about this, but..." (except perhaps a piece that omits this confession when it's really quite necessary). On E2 in particular, it's the only way we can obtain some information: if you're an expert in some obscure field (1st century Chinese history, MRI physics, whatever) then you damn well better write about it, because nobody else will.

Unfortunately, some writers use this principle to justify rabid narcissism: deciding (apparently) that they only know about themselves, they churn out dozens of morbidly emotional pieces overfilled with excruciatingly banal details about their putatively fascinating life.

Two well-known writers have spoken out against the narcissistic interpretation of this principle. In The Elements of Style, E. B. White twice admonishes writers to leave themselves out of their writing:

Place yourself in the background. Write in a way that draws the reader's attention to the sense and substance of the writing, rather than to the mood and temper of the author. If the writing is solid and good, the mood and temper of the writer will eventually be revealed and not at the expense of the work.
To air one's views to imply that the demand for them is brisk, which may not be the case.

In a recent talk, Ken Kesey put it more bluntly:

People tell you to write what you know, to write about yourself--bullshit, I say. Don't write about yourself. You are boring. If you were really interesting, you wouldn't have time to sit around and write a fucking novel.

This principle doesn't mean that you should pick topics at random: writers do best when they write about topics in which they're interested. Nor should it be interpreted to mean that you should never use personal anecdotes. On the contrary--anecdotes can effectively illustrate a particular point, bringing it home to the reader in a way that abstract rhetoric cannot, and they can provide a window into the lives of others, letting you know that you're not the only one who feels or thinks a certain way. Without this higher purpose, a personal anecdote by itself, while potentially interesting, provides no vital facts, imparts no new ideas, and adds little that is timeless or enduring....which is why we have a separate place for them on Everything.