Using MIME types to solve the one click subscription problem is more diffficult for weblog tools to implement than the other two approaches favored by�news aggregators�and requires changing web server configurations as well which while the other approaches do not. Although the architecure astronauts�will rail against the URI scheme based approach it is unlikely that anyone who looks dispassionately at all three approaches will choose to use MIME types to solve this problem.�
Of course, since one of the main forces behind the ATOM movement has stated that MIME types will be the mechanism used for�performing one click subscription to ATOM feeds�this just seems like one more reason for me to be skeptical about the benefits of adopting the ATOM syndication format.