IPFS (Interplanetary File System) shares the same YaCy philosophy of a distributed network. In what ways might it be possible for the IPFS project and developers to help YaCy?
For example, caching of web crawl results and indexes might be more effective if the data were shared as a file on IPFS. You could create an IPNS (Inter Planetary Name System) folder hash, which would remain constant, then into that folder keep your ever updated index. You might be able make your index readily available to others by publishing the IPNS hash. (If you use the IPFS hash, it would need to be updated every time your index changed.)