E-mail fields are rarely getting used for valid email adresses, so why not extent their functionality? They could be used for web adresses, for instance. Kareha / wakaba would only have to check if it's a somehow semantically correct adress and then make it a simple link (instead of a mailto: link) - and perhaps automatically add a http:// in front if that's missing.
In seeing Shii's more recent "vBulletin" lookalike job with shiistyle, removing the email field I have to strongly dislike it. Even though the email field is somewhat useless except for people having a good o' sage, myself being somewhat geriatric about think the field should stay, even if it isn't used for its desired purpose. It's something that isn't being abused.