Sendgrid’s a great way to send email from your app. They provide statistics, reliable delivery, and a fantastic XML/JSON API. If you’re using Ruby, I recommend checkout out Sendgrid Toolkit, which I just found out about.
Sendgrid Toolkit is pretty much a thin wrapper using jnunemaker’s HTTParty, which I haven’t heard about till now. HTTParty’s a pretty cool way to painlessly create an interface to a Web API.
Sendgrid Toolkit’s use of HTTParty makes adding functionality very easy. I added bounce retrieve and delete functionality by merely adding the small number of lines seen in the code sample.