MIME was hugely influential. Besides the bulk of all email being in MIME format, it also popularized: * MIME types, now called media types; a compound identifi

MIME was hugely influential. Besides the bulk of all email being in MIME format, it also popularized: * MIME types, now called media types; a compound identifier for formats of data interchange. Media types are officially maintained by the IANA Media Type Registry [1]. * Base64. MIME lifted the encoding from the PEM RFC [2][3] but MIME brought it to prominence. * Content-Disposition: a header to specify intended presentation semantics. Later lifted into HTTP. * Other "Content-" headers, like Content-Location. These were also adopted by HTTP. Furthermore, the various multipart mediatypes imbued adjacent parts with additional semantics, like "multipart/mixed" to signal that the child nodes are independent, but ordered, and "multipart/alternative" to signal that the child nodes are to be treated as alternate versions of the same content, in order of increasing richness. The thorough design around multiparts meant that a MIME document is a tree, where every node is a subdocument with headers, preamble, body, body, and epilogue. It was suitable to use as a nesting data structure, albeit it most applications opted for binary formats instead. Later, when text-based formats became popular, they often invented XML-based formats to capture a similar tree. [1] https://www.iana.org/assignments/media-types/media-types.xhtml https://www.iana.org/assignments/media-types/media-types.xht... [2] https://tools.ietf.org/html/rfc989#section-4.3 https://tools.ietf.org/html/rfc989#section-4.3 [3] https://tools.ietf.org/html/rfc1421#section-4.3.2.4 https://tools.ietf.org/html/rfc1421#section-4.3.2.4