On Dec 17 2004, Keith Moore wrote:
since you don't want the copy of annotations to be implicit in copying
the message, I conclude that annotations should not be stored as part
of that self-contained object.
(yes, you could require that every MUA edit out annotations from the
message header before forwarding them, but this isn't backward
compatible. it's also optimizing for the uncommon case)
There really needs to be some common idea of what annotations represent.
I'll discuss your listed features a little more to see what kind
of questions they suggest.
The important features are (a) that they're associated with the
message but not inherently part of the message and (b) that they can
be manipulated in useful ways independently from the message.
If we take (a) literally, then virtually any type of derived information
qualify as annotations. For example, decoded images, or even the whole
display rendered message can be seen as derived from the literal contents of
the message. Such a display can certainly be manipulated in useful ways
(e.g. change fonts on the fly, etc.)
But that seems too general. The displayed message is ephemeral, it is
never stored separately. It seems to me there at least needs to be
property (c) annotations are persistent. Of course this means that the
question of how and where they are stored is fundamental. But it also
means that easily (re)generated information does not and should not
constitute an annotation.
There is also the question of how long such information is valid.
If annotations are stored separately, then their natural lifetime
must be short or medium at most. Certainly, a typical message archive
would not be an appropriate place for them.
Another question: who or what are they for? Are they only for the human,
are they for both human and machine, or can they be solely for the machine?
I don't think annotations should be solely or principally for the machine.
[assume annotations stored with message headers]
so if the user decides that he's going to forward some message from the
webmail client, should the webmail client send annotations along with
that forwarded message or not? if the annotations are stored in the
message header, the webmail client will include them in the forwarded
message (assuming it forwards as an attachment, which everybody should
be doing these days), because it doesn't know any better. if the
annotations are stored out-of-band, the webmail client will not forward
them, because it is not aware of them. OTOH the fancy IMAP client can
give the user the option of forwarding the annotations because it's
explicitly aware of them. for that matter it can let the user select
which annotations to forward and which ones to keep private.
I think in this example, you implicitly take annotations to be by and
for the human message recipient. Forwarding a message breaks this
paradigm as the forwardee obtains a message containing annotations by
somebody else. This is true even for annotations that are not private.
I don't think the forwarding problem is in itself sufficient to rule
out storage inside the message, as it's always possible to, say,
encrypt annotations solely for the originating user. In your example,
the IMAP client would know how to encryt/decrypt the annotation, while
the webmail client would not. The forwardee would have a fully annotated
message without the ability to read the private annotations.
--
Laird Breyer.