Why does smoke disperse but clouds seem to stick together?

The particles that make up smoke and clouds have important differences, which explains how they appear.

ASK ALLISTER: Could cloud seeding help extinguish wildfires?

Why do clouds 'clump' together? Wouldn't it make much more sense or be much more likely for them to distribute evenly? - Quora

How do clouds in the sky maintain a relative shape over time instead of just wispily blending with the air around it like smoke in wind? - Quora

Towering wildfire clouds have big impacts on the stratosphere - NOAA Research

How Smoke Machines Work - All Kinds

What Happens When You Fly a Science Plane Through Wildfire Smoke

Cliff Mass Weather Blog: Is Wildfire Smoke Making Our Fog More Persistent?

Province of Manitoba agriculture - Smoke Dispersion: the Key to it All

What makes clouds stick together? - Quora

Australia fires spewed as much smoke into stratosphere as volcano: study