Phosphoinositides (PIs) have long been known to have important roles in cell signalling. During the past decade, it has become clear that these lipids also act as constitutive signals that aid in defining organelle identity, and are short‐lived recruiters and regulators of cytoskeletal and membrane dynamics. Recent studies have provided important clues as to how regulated activation of PI‐metabolizing enzymes and recruitment of their binding proteins might cooperate in targeting distinct pools of PIs to different cell physiological functions.