The problem Fluid Finance solves

Fluid Finance is currently a set of two protocols - Options Liquidity Mining Protocol & Lend n Borrow Protocol.
Both try to explore the unique capabilities of Flow's resource based asset management.

Unlike traditional OLM, Fluid finance manages the users payout tokens directly in their account and yet locks it away from them until they redeem it. The ownership in this case is like user => options tokens => payout tokens that the option token is supposed to back. This gives the guarantee that the options are backed properly and also allows for the emergence of a payout backed options market.

In Fluid Finance's Lend & Borrow protocol, the liquidity positions of each user is managed with the help of liquidity Buckets. Each bucket is an isolated liquidity position and liquidation of one doesn't affect other. This allows for far greater flexibility in how you lend & borrow capital and also how much risk you want to take on different set of tokens. Each bucket in itself is also a resource which allows for the possibility of a never seen before liquidity bucket market. Buckets can be freely traded without risk to the protocol itself or to the users.

Challenges I ran into

Coming from a solidity background, learning Flow ecosystem, especially Cadence was a slow process. I had to change my mental model around how contracts and assets are supposed to work. But it was good to see Flow's unique way of managing resources and capabilities
I learned them mostly through the docs and the tutorial on flow dev site.