as others have said the claims page is the big one that should have gone to everyone...at the very least there should have been 1 email to say 'here's the claim page, for further info see this forum thread/twitter feed/website'
I agree, because of the certificate issues on bitcoinica, many people (me included) would have seen the following page in chrome:

Without email notification this means a lot of people were completely unable to discover the claims page, much less trust their personal info to it.