It's tempting to have the freedom to say whatever you want, under a cover of anonymity. But what happens if you're writing anonymously and someone "outs" you? Perhaps you have this reaction:
It happened to me, back in 1996. Some moron hack bloviating boulevardier editor doofus was having a drink with a humorless droid from that very same party-pooping organization that killed Fake Steve, and happened to mention my very well-kept secret identity. An article ensued, which attempted to inflict a mortal wound on my fake person. I survived, possibly because my fake personality has more friends than my real one. But I've never been able to be purely fake again.Maybe you are not important enough to be outed in the New York Times. But believe me, you're going to be outed all the same. [interesting story redacted here] If secrecy doesn't last even when it's backed up by the threat of a lawsuit, what hope do you have of maintaining anonymity?
Rather than risk going through a sinking feeling in my stomach, I just started out non-fake. I also save posts in my drafts folder. And go back and delete them after a few days, because by then it's obvious that it's a story that I can not relate in public.