OK...I do not know all this to be fact, but by looking-up definitions it appears that:

Soil is what you dig out of the rose garden at the park. (clay or sandy base, ammendments, compost, rocks, bugs, forrest leaf-litter, weed seeds, cat shit) Some folks around the cannabis community used to call this dirt, and should be avoided if possible.

Soilless products are individual components mixed together to create a growing medium. It's a method of controlling the growing medium, to meet a gardeners needs. Gardeners have different needs, so different soilless mixes are available. Cactus mixes, African Violet mixes, seedling mixes...
That's my story, and I'm sticking to it. (until I'm schooled otherwise, lol)

This may be a bad explination, but I think I get the idea, lol.

Anyway, do you put brownish stuff in a pot, add plant, then grow/water the plant, or do you put a plant in a pot, and splash water directly on it's roots from a reservoir?

Perhaps someone else has a better explination as I'm really not 100% positive?