Good rule of thumb: don't email anything you wouldn't want to see in print.
In what the FT calls "one of the highest profile libel cases in England to focus largely on blog postings and electronic traffic", Sir Martin Sorrell, founder of WPP, is suing two former business associates. These associates are alleged to have sent a company-wide email to their ex-WPP subsidiary referring to the WPP founder and Ms. Weber [a colleague] as "the mad dwarf and the nympho schizo". (from the Telegraph, UK, 15.03.2007), and set up a libelous blog.
If anyone can find the blog, please send it my way. you'll have my undying love and a featured post.