Not on the desktop but on mobiles I think the era of E-mail clients will soon be over. Just like the era of filemanagers will be over. A person who’s using a mobile or a phone doesn’t really want to start and stop applications. Those users don’t start and stop applications to receive phonecalls and text messages. Why would they want to start and stop E-mail clients?
Not only that. People also want their text messages, E-mails, history of calls, meetings, contacts and photos to be integrated.
When we search for a meeting, we want to find the photos we took at that meeting. We also want to find the contacts that were at that meeting. We want to find the invitation E-mail and all the replies to the invitation. And when we select a contact, we want to see a tree of E-mail discussions that we once had with the contact.
On a mobile we don’t want one big application that does all this. Instead we want all applications to integrate with all this information. And we want it to be very easy for application developers to integrate with this system. An application framework.
This will be the purpose of Tracker on mobiles.
This means that the concept of an E-mail client will eventually be moved to the background of the mobile device. E-mail must just be there, not started. Something must communicate with the IMAP server whenever needed. Meanwhile all applications on the mobile need to have easy access to the metadata of the E-mails. It must be easy for them to get a MIME part of an E-mail, perhaps as a InputStream?
The combination of E-mail metadata querying and handling of the E-mail’s MIME parts is what I refer to as “E-mail as a service”. Some people in the past tried to explain me that if they would just put JavaMail’s API over D-Bus that this would already solve “E-mail as a service”. I don’t think this is true. Camel, which had its API based on JavaMail, offers a truly weak query interface. It’s for example not possible to ask for MIME parts that are images that have a specific Exif tag set.
That’s of course because it’s not Camel’s purpose to do metadata indexing of the attachments. But that was yesterday. Yesterday was boring.
With modern IMAP servers that have the CONVERT capability it will be possible to ask for a converted MIME part of an E-mail. Converted to Exif plain-text data. Meaning that we don’t have to fetch 5MB of JPEG data just to read a few hundred bytes of Exif metadata.
Meanwhile normal IMAP servers already offer ENVELOPE and BODYSTRUCTURE which of course gives us a lot of metadata too.
To assist people who want to write a “E-mail as a service” D-Bus service today I have decided to write a document that explains some of the capabilities of modern IMAP.
I think the future of E-mail “infrastructure” lies in:
Using an RDF store that can be accessed using SPARQL, like Tracker. This stores the ENVELOPEs and BODYSTRUCTUREs of your E-mails next to the attachment’s other metadata triples. The query language can then be used to query against metadata found by analyzers like Tracker’s own extractors and/or Strigi’s StreamAnalyzer as well as metadata coming from IMAP itself.
People who saw my presentation at FOSDEM already know that we are planning to push Tracker in the direction of SPARQL + Nepomuk as ontology. Meanwhile we are in discussion with the Xesam and Nepomuk people to change the Nepomuk Message Ontology to be suitable for this. As a result Evgeny Egorochkin made this proposal.
Having a small service for dealing with E-mail specific things. Like getting the contents of the MIME parts as streams. Requesting them to be downloaded if they aren’t cached locally yet. Requesting a CONVERTed version of them.
There are some experiments happening that will implement this capability. It’s all still very early. If I ever start a Tinymail 2.0, I will probably make it focus primarily on this.
I don’t think the conventional E-mail client will survive for very long. Especially not on mobiles where “integration” is far more important for the end-user.
Every (mobile) application can soon become as capable of handling E-mail as what we today call “the E-mail client”. At least from the point of view of the user. In reality a desktop service will solve the hard stuff.