Looked at APML (Attention Profiling Mark-up Language) spec this morning. First impressions are that it's doesn't offer enough and unnecessarily verbose. Essentially, APML models a person's attention with an open set of 'concepts', name/value pairs where name is subject of interest and value is degree of interest or disinterest (-1.0 to +1.0).
Their model for attention seem to simple. For example, time factor has strong influence on what a person is interested in. How do you represent duration and immediacy of interest? Also, interest is often goal-driven and expire as soon as associated goal is met. For example, I was interested in Prius when I was looking for a car for my wife but now I am not. Note that time and goal are related factors.

Anyway, I've joined APML mailing list.