APML allows you to share your own personal Attention Profile in much the same way that OPML allows the exchange of reading lists between News Readers. The idea is to compress all forms of Attention Data into a portable file format containing a description of your ranked interests.
From Master New Media
...Attention profiling is quite possibly the next wave of smarter, more relevant web browsing. APML is an emerging standard that promises to make it much easier for websites and services to cater to your exact tastes, reducing the information overload of seemingly endless web content...
...It is already being supported by several prominent online destinations, and shows no signs of slowing down...
Getting an APML file
A growing number of services support APML export. As you use them, they will update your APML file and allow you to export it.
Using an APML file
A growing number of services support APML import. They allow you to upload your APML file to get an instant understanding of your interests.