The most useful feature for me personally was being able to create automated emails using templates I could use over and over again instead of having to change it each time I send out an email. The interface is clunky and not very intuitive - which makes sense given how old this product has been around since 2006 when Gmail first came out. If you want something simple to do bulk emailing then go with MailChimp or Constant Contact but if you're looking for something more modern and robust then look elsewhere! We were trying to simplify our mailings from events we held at our organization by creating pre-made emails people can just click'send' without needing to edit them every single time.