If you develop Wordpress locally and try to use the mail function, you may encounter problem. The PHP mail function cannot send mail out. To solve the problem, you can install a free local mail server on your computer, and test it locally.
First, read my another post here about how to install the local mail server.
After that, you can go to WordPress Admin area and change some of the user email to xxx@example.com, and you should be able to send mail in WordPress.
Hope this helps!
