Jessica Tallon's implementation of petnames and edge names was extremely simple within the paper davexunit linked, but used in-band mechanisms to communicate edge names that didn't require any sort of large trusted authority. You could retrieve them directly from fellow peers, who could publish their current set of edge names. This even works in a p2p context over ocapn, etc. The implementation was naive but it did work and used a publish-subscribe mechanism directly from other peers.

That said, edge names are only one way to share contacts. In fact "share contact" on peoples' phones is a great way to have contextual sharing: "Oh, let me introduce you to my friend Dave. Here's Dave's contact info!"

At any rate, petnames aren't a particular technology, they're a design space of "Secure UI/UX". However I do agree more research needs to be done in that space; we've only barely begun to scratch the surface.