+1 if you log in to DW and submit your address book, and I have this setting on, you will NOT see me in the results list. However, I will get an email/notification that says "Denise has joined Dreamwidth, here is her account!" -- gives me the choice on a one-by-one basis to expose my account or not

We like that bit about mark's suggestion, too. Our problem isn't similar to dreamwriteremmy's, many accounts with the same address, but rather that we use the same email address on FB and several other places where we don't want IRL people to be able to track us back to our journal here (for obvious reasons).