The Lindy effect is an affect proposed by Nassim Nicholas-Taleb and others. It states that how long something has survived in the past is predictive of how long the thing will survive unto the future. More precisely, the Lindy effect predicts that the ladder will be equal to a former, i.e., if a restaurant or technology has been around for 20 years, it will likely survive for another 20 years. According to the theory, mortality decreases with age. As Taleb put it, when waiting for a project to be completed, "the longer you wait, the longer you will be expected to wait."
The Lindy effect is related to power laws. Lindy effects apply to things whose lifespans exhibit power Pareto distributions. It would not apply to, say, human lifespans, which do not exhibit Pareto distributions.
The Lindy effect also relates to evolutionary fitness. The fact that something has survived for a long time is a demonstration of its fitness, and therefore its ability to survive in the future.