How does crul handle the dynamic nature of the web?

Yes, content changes, but so does structure. If I'm interested in content that shows up in a news feed div, and that div is renamed or moved as part of a site redesign, what happens?

I've worked on a bunch of tools in the past that do similar things, and structural changes were the kryptonite for all of them.

A secondary problem is when you use particular content as a reference point, and that content is later updated. Now your reference point is gone!