I will attach a comparison of good and bad pools below to prevent others from claiming I am advertising. I have removed the pool names and am purely sharing useful information. Many pool owners provide vague introductions, fearing that you might discover their tricks.
Many people randomly choose a pool to delegate when pledging ADA.
As a result, the returns are low, block production is unstable, and there may even be long periods without rewards.

Pledge (self-staking) is the ADA that the pool owner puts into the pool.
This is not your funds, but rather the operator's 'margin'.
Why is it important?
Because this money represents that the pool owner has 'skin in the game'.