(Non-normative) It is common for Web-based services to establish default actions for content based on the MIME type value sent in HTTP headers. For example, the "text/html" MIME type is what normally causes browsers to interpret the content of a web page as presentation-oriented markup, verus "text/plain" which would cause the markup to be displayed literally. A DITA MIME type enables applications to recognize content as DITA to enable special services such as semantically-informed search indexing or on-the-fly rendering in the browser.
The OASIS DITA Technical Committee has requested the registration of "application/dita+xml" with the IANA organization as the formally recognized DITA MIME type. This process is in progress, however the details are public so that implementors can make early use of the proposed value.
More information about the proposal is documented in this note of transmittal to OASIS for registration of the DITA MIME type: http://lists.oasis-open.org/archives/dita/200806/msg00008.html