what is mailxel?

Looking back at my 10+ years worth of personal mails, I realized that mails, to me, are much more than a communication instrument. They do document my life, and serve - thanks to the instrinsic annotation with addressee, subject and descriptive text - as the best personal document management system I know. However, handling large volumes of mail data is challenging and, to my surprise, not supported by todays mail clients. The classical storage formats do not facilitate efficient search or data access, nor does IMAP or the commercial solutions I know. Also, GTD processes are typically added as second-priority features - in short: reason enough for the valiant developer to start his own project mailxel.