Current state of discussion is:

Every type of resource has a base priority (image, pixel > ads). Actual load priority is influenced by position in viewport. Highest priority for visible resources, lower priority for resources that are about to becomes visible.

For the base priority we need thresholds: Based on prerender mode we may never want to render

• any resource
• ads, pixels (Even though pixels are high priority during normal loading or even special enough to be out of band)

During scrolling we never want to trigger loading an ad (I think, unless that ends up not feeling good due to incremental rendering).