How do you read? (And Yellowstone is a supervolcano)
superkarn: I think a lot of it has to do with your interests.  For example, you're a HN reader and you come away with "Yellowstone == supervolcano."  A new mom would probably read the quoted text and think "Yellowstone is dangerous, don't take the family there."  A kid who is into fireworks and explosions might remember "TNT the size of Rhode Island, cool!"When I read, I usually just remember the big picture plus the small details that I personally find fascinating.