New Disposition type: Inline Subordinate

Hello 'email people'

RFC 2183 defines two basic disposition types, i.e. "inline" and "attachment".
But sometimes we need a more elaborate presentation than the existing disposition 
types. For example, the current advertisement way in Email or Webpage is very 
"evil", sometimes it is difficult for the users to distinguish the real contents 
from advertisement, and this is disgusting or confusing. Nowadays many email 
service providers insert advertisements in the user's email. The inserted 
advertisements normally are displayed at the end of the email, but sometimes the 
boundary between advertisements and other real contents is not clear. So that 
the recipient may be misunderstanding, the advertisements might be regarded as 
the real contents the sender writes.

However, advertisement is absolutely necessary for the development of internet 
and mobile applications. In order not to interfere with users much, the technology 
for sending advertisement kindly is needed. Email, MMS, IM and SIP messages may 
use MIME as their content body, the advertisement could also be inserted into 
the message body as a MIME content. Maybe a new disposition type can be defined 
to help users distinguish the advertisement and the real contents. Its definition 
is like this:

A bodypart should be marked "inline-subordinate" if it is intended to be displayed automatically upon display of the message, but it should not block other displayed bodyparts, e.g., bodyparts with a regular "inline" disposition type. It is RECOMMENDED that the client render the content marked by inline-subordinate in a separate place away from other inline contents.

Opinion?

Cheers,
Qian