Acetone nail polish removers contain a very powerful solvent that is harsh and has a strong chemical odor. Using acetone as the main solvent, is effective at dissolving and removing nail polish quickly, yet it and is very harsh toward nails, cuticle and skin. It removes a lot of natural oils from your skin and, a clear sign of it's effect, is that it will look really white, even if you haven't used too much of it.
Soy based nail polish removers don't contain acetone. The're non-toxic, a 100% biodegradable alternative to harsh acetone based nail polish removers. These nontoxic polish removers mainly contain mixtures of naturally derived esters, which are light, typically nongreasy oils. Basically they use the same chemistry as acetone-based removers: They act as solvents to soften and dissolve nail polish. But they also moisturize and condition the nails on every use, versus drying out the nails like typical removers.
For anyone used to traditional nail polish remover, the switch to soy-based versions will likely take some getting used to, but then again, no addiction comes without its downsides.