I wasn't really trying to scare several of you into seriously considering friendslocking all your posts when I posted the audience question!
I think it's very important that you all know that public posts can be cached by search engines for years to come, and that there's a chance that the Internet Archive will permanently cache a random and rare selection of your posts. It's important that once every blue moon you put your name into a search engine and see what the world can find out about you. Be aware that if your real name, your email address alias, or any of your common nicknames and personal details are attached to your LJ or you write about them, then those things too can end up indexed by search engines.
But as long as you go into this with open eyes and consciously make the decision to post whatever you like online, then that's what matters. After all, there are a great many of you I never could have found to have the pleasure of reading your journals if you made ALL your posts friendslocked!