Created in 2004, Remember The Milk, or RTM, is considered one of the pioneers in terms of GTD and has influenced many applications
RTM allows the creation of lists of personal tasks but also of “Smart Lists”, which automatically filter the tasks – whatever their original list – according to different criteria (keyword, deadline, priority level … .).
One of the strong points of RTM is its integration with several services like Gmail, Google Calendar, Evernote but also Siri and Twitter. However, there are some limitations. So if it is possible to assign tasks to other people, only two lists can be shared in the free version. Also the reminders will only be sent by SMS, instant messaging or Twitter but it will take a premium account to synchronize them with the mobile application on Android, iOS or BlackBerry 10.