trt, applications like Microsoft Word have features which recognise various formats and do things to them which they think you will want. Mostly they involve things like turning the first letters of sentences into capitals, removing spaces before question marks and exclamation marks, turning double quotes into curly quotes, but they also recognise email addresses and turn them into hyperlinks. When you click one of these, your email application starts up and a new email is created for you, but if you don't want this and just want the email address to be in plain text, you can do as Edmund suggests.