If we ever do implement a message export feature (which we may; we've talked about it a number of times), a database-like format will almost certainly not be the first thing we go for. A much higher percentage of our players will likely want human-readable output rather than machine-processable.
That's not to say that this will never happen, but it's definitely a lower priority than an HTML or rich-text message export.
HTML with properly tagged classes are fine too! So its easier to use JS to get content... It would be really great if there is timestamp not current "days ago".
