Since office 2007 they use word to render HTML mail. Probably mostly because of security reasons because at the time their other option was IE which lead to man

Since office 2007 they use word to render HTML mail. Probably mostly because of security reasons because at the time their other option was IE which lead to many previous security flaws. Word isn't much safer but at least it is under the Office team's control plus it's less widely deployed than IE was at the time. It also has way fewer features with regards to HTML rendering which helps reducing the attack surface. On the other hand, as it's neither browser nor HTML editor, its HTML rendering capabilities are never improved because it's no priority. And thus HTML mail is stuck at tables, font tags and spacer gifs for the rest of eternity. Thank you Microsoft. (OTOH, whatever helps discourage HTML mails and encourage plain text is a good thing in my book. And now, get off my lawn)