Products: Observe the “Desire Path”
From Wikipedia:
Desire paths can be a path created as a consequence of erosion caused by human or animal foot-fall or traffic. The path usually represents the shortest or most easily navigated route between an origin and destination.
Further:
A representative example is Twitter, which has “paved” a number of desire paths by integrating them into the service, including @ mentions, hashtags, and group discussions, although not always precisely mimicking the behaviors of users