In their heyday, webrings provided discoverability for groups of topical websites but also facilitated social aspects of the web before social media provided easy access to social graphs.
Today, there is increasing disillusionment with the proliferation of low effort posting that social media encourages. In dark corners of the internet, unenlightened by social media, there is an interest in creating decentralized webrings, and nostr seems to be to be a good way to get that started.