This plugin is awesome for folks who are hosting their web site on a service where the SMTP server could be blocked for being spam. A good example would be if your blog is hosted on an Amazon EC2 instance, where both MSN/Hotmail and Yahoo block email messages from. This plugin will allow you to send your mail from a specific SMTP server which will circumvent this problem. If you're doing a personal blog with a low number of Emails a day, this plugin paired with a Gmail/SMTP account is unbeatable.
Great work Scott!