Feats are actions performed by various characters/entities that are used to show their power. Feats are one of the most important ways to gauge a character's power, and therefore, they are also the main points of argument on almost any thread. There are different types of feats, such as strength feats, speed feats, durability feats, destructive power feats, intelligence/prep feats, etc. Some feats are more useful than others since they are more easily quantified.
For example, a character dodging a bullet from what looks like a Glock 17 can be analysed since we all know the muzzle velocity. A character dodging a Ray Gun beam from an unknown type of weapon cannot be analysed, since we don't know how fast it moves.
Feats are often collected and explained in respect threads. Characters/Universes with a lot of hyperbole claims and few feedbacks to back them up are generally looked upon with skepticism.
However, even feats can be discredited if they are unsupported by context of the story, whether being far outliers, or retconned out of canonization.
Note: The information contained here is taken from the VS Battles wiki. On this wiki, natrually, feats are decided entirely by the creators of a given character, so they are less useful. They are still an option for character profiles, so they may act as an effective guide to a character's exact strength.