The Levy flight
Clay Shirky taught me this very cool mathematical concept that shows up in nature, and now in marketing and social media.
An animal that forages will hang out in a small area, looking for nuts or berries, then will realize it has used up all the likely sources in this spot. It will then head off in a random direction, walk many paces, and start foraging again. When you plot the Levy flight, it looks like this:
Someone discovers your site. They poke and prod and join and return and return again. Then they feel as though there's no more benefit and they move on, surfing until they find another place to forage.
Someone finds your restaurant. They love it. They return with friends. They hang out and become regulars for a while. Then they get bored and start browsing again.
Adding the Levy flight to your understanding is a much more nuanced representation of consumer behavior than solely thinking about the ideas of brand loyalty or random web surfing.