What it means
In crypto, one forced sale can push price into the next set of liquidations, a cascade that moves price fast with no news.
In practice
Exchanges close a leveraged position automatically once losses eat through the margin behind it. Traders work out the liquidation price before entering and make sure their own stop-loss sits well before it.
Clusters of estimated liquidation levels are watched as targets. Because forced closes are market orders, price that reaches a cluster often accelerates through it and then turns once the forced selling or buying is finished.
What to watch for
Liquidation is the worst possible exit: it happens at market, in a fast move, often with an extra fee, and it takes the whole margin. A stop-loss sized to a small fixed risk means you should never get near it.