This Whiteboard Friday video discusses the concept of the ideagraph, or how seemingly random topics can be related because of human preferences and connections. The example here is that cyclists may have a common liking of eggplants. This is not an obvious connection but it had the possibility of creating high converting traffic if you can find the right associations. This currently exists in the current layouts of grocery stores. Milk is placed in the back to make people walk through the store to it and items that people looking for milk are likely to buy are placed along the route.
Online this concept can be utilized in several ways. First, G+ authorship can help search engines understand these connections in a way that their “words and links” structure does not. Finding these connections can also help guide content creation and keyword research. Examples of places where these connections can be researched/found are Facebook Ad Planner, collaborative Filters (“people that bought X also bought X) and Followerwonk.