Linked from
The 8 pages that link to True anomaly, each with the reason it gives.
Orbital eccentricityRelated: It locates the body along an eccentric orbit as its distance changes.
Vis-viva equationRelated: It locates the body along its orbit, where the equation gives its speed.
PeriapsisRelated: It measures an object's angular position from periapsis.
Kepler orbitRelated: It specifies where a body lies along its conic orbit.