It is currently only possible to use the messaging app to send a message to a conversation which already exists. It would be great to be able to start a conversation with:

• A contact with whom we are not already in a conversation
• An arbitrary phone number

There are many good ways this could be implemented. One idea is to add a new GUI page which shows all contacts and offers a box to enter a phone number. Another idea is to put all contacts into the recent conversations list, even those with whom we have no current conversation, and simply sort contacts with no attached conversation to the bottom.

In any case, if the selected contact already has a conversation, open that conversation. Otherwise, open blank conversation page. The same behavior ought to apply if a phone number is entered which matches an existing contact, but make sure the matched contact isn't a surprise to the user!

Making a new conversation will require some changes to the ConversationDbusInterface API, since it currently only deals with existing conversation IDs.