What Is Liquidity Pooling?
A liquidity provider is a stakeholder that provides liquidity (a liquidity pair) into a pool that is needed to run a decentralised exchange. He gets rewarded with a share of the trading fees generated with that pool which is reflected in the APY. At THORChain a liquidity provider has two options how to provide liquidity: symmetrical or asymmetrical.
Symmetrical means 50% Rune and 50% the asset you've chosen. Asymmetrical means 100% in your chosen asset. It is important to note that if you provide liquidity asymmetrical, a swap is pursued in the back, that leads to a symmetrical allocation anyway.
This means a liquidity provider is always exposed to two assets: Rune and your chosen asset. The APY is earned on both of those asset and auto-compounded in the pool.

Pooling Page