The problem Jab Opensea mets The Graph solves

We wanted to help creators artists designers who are on Opensea and want to identify their HOLDRs are. In other words if creators wanted to show their gratitude to user for acquiring their NFTs. There’s no easy way to do that without something like the Graph Indexing the contract and keeping track of who holds what.

The Opensea subgraph is a subgraph deployed to The Graph’s Hosted service that unlocks 4,853 entites of data available in the short time it’s been deployed , it’s been used by creators and other and people building to visualize what is happening on gas-free marketplace for NFTs on Polygon. -Open Sea

Challenges I ran into

No real knowledge of the contract. Had to monitor and watch what was happening in the Poly scan explorer to find/map all the relevant methods that would ultimately lead to the data we are now making available through the subgraph