Terran internet encyclopedia “Reddit” frames cuil theory. This may or may not be the item mentioned in HSD 1.0 to a Terran database referencing Cuil Theory. In Sound and Silence the lore goes into more detail about Transcendent research on Terra, which is more solidly in the science-fictional timeline.
Reference: Hazy reference in 1.0 color text for Cuil and transcendent implants referencing a 20th century database.
Date Notes: First appearance of cuil “hamburger” meme on Reddit, which seems like the most likely reference for this one!