Microsoft is reportedly working on a new mobile app called Flow, designed to work with Outlook, which offers rapid email exchange that closely resembles instant messaging. “Correspondence with Flow will likely look similar to exchanges on popular messaging apps such as WhatsApp, Facebook Messenger, and Apple’s iMessage, though it’s email that’s behind the system,” reports Digital Trends. According to the leaked product description, Flow will offer “fast, fluid, natural conversations: No subject lines, salutations, or signatures.” If message recipients do not have Flow, incoming messages will simply appear in their inbox as regular email messages.