knc1, the forum software we're still using is not UTF-8 aware. It is not enough to simply convert the underlying database to UTF-8 and to change the HTML headers accordingly; all string-related operations need to be replaced too when byte count matters. We did a sandbox in the past doing all the changes ourselves, and it seemed to have worked, but honestly, since we are planning to switch the forum software as soon as a adequate candidate is in sight, we don't want to apply any more custom changes than necessary. It might get harder to upgrade to the other forum software otherwise. Finding the right forum software we could migrate to is a real nightmare.
I don't think the ampersand issue described here by geekmaster is related to character-set issues as the ampersand should be part of either character-set.