The current implementation of Email System in PLOTS2 doesn't implement Active Jobs i.e queue feature because it is currently using rails 4.1. And rails 4.1 doesn't implement Active Jobs on its own. We have to ways to resolve this either include activejob gem or upgrade to rails 4.2 (we will go with this). So currently, mails are sended synchronously. And if the sending of mail is failed due to some reason or we don't want to send the mail at the time of request/response or if we want that a mail should be sent after (1 day or any specific period of time) we can't implement it now. Sometimes, we have to run jobs at particular intervals to, say, backup logs, send emails, etc. In rails application we can schedule such tasks using the whenever gem. For integrating cron jobs with the plots2 we can implement whenever gem which will be very useful in sending daily "batch digest" email to the subscribers. We can specify the time when the email should be sent. More details on implementation is in Implementation part. Another feature is the reply-by-email feature using mailman gem. Feature that we can implement is of reply by tweet which is very convenient and easy for the user to do.