I do not see any paricular risk in exposing the hashed list. the reason behind the hashed list is exactly that we want to allow publishing without any risk to publish direct link to child porn contents or other shit. anyhow i'm really interested in others opinions.
i agree on the SHA-256; the reason why we have not changed it since time is that we don't want to loose the current banned list. in fact no one is keeping the cleartext version of the banned links.
Giovanni