Excerpt from the original CRV manual by Paul H. Smith:

Virtually synonymous with the previously considered term “AOL Matching”, AOL/Signal occurs when an AOL produced by the viewer’s analytic mental machinery almost exactly matches the site, and the viewer can to some extent “look” through the AOL image to perceive the actual site. The advantage of AOL/S in Stage IV is that it allows the information to be used without calling a break. One can ask, “What is this trying to tell me about the site?” As an example, the viewer may perceive the Verazzano Narrows Bridge when in fact the site is actually the George Washington Bridge.