[nedrocks]

This assumes the client can keep state in a more reasonable way than a server can piece it together. Definitely a stateful event is more powerful but is likely more lossy.

From what I've seen tracking simple events and then piecing them together en masse tends to show up significantly more frequently.

[luckylion]

Sure, I mean, it's also easier because you don't have to know the questions you might want answered.

Given the very private nature of the data ("he read Marx and Mao, and read some sections carefully!"), vacuuming up as much as possible doesn't sound like a good idea. Add to that the almost chronic inability of large corporations to protect data, they really should start treating data collection as a liability rather than an opportunity.