Hmm. Part of the problem with the cool stuff that gmail can do with embedded structured data is that, well, this stuff works the way it does because email has a gmail monoculture. Developing open standards for the very different types of data one might want to structure is an order of magnitude more difficult.

hmm, I wonder what kind of cool info I can get running filebeat into an elk stack for my mail directory. If the mail spool is a log, then use log analysis tools on it.