Decentralized Identifiers are supposedly a standard that will allow anyone (or anything) to have an online identity. The DID is a URI like
did:<method>:<data> in which
<method> determines how to interpret the
<data>. The data is generally a public key in some cryptographic system or shitcoin blockchain, or a naked key, or a DNS-backed web address.
Some of the DID proponents argue that this is for maximum interoperability, since any new system can be supported under the same standard, i.e. supposedly an application could “support DIDs” (as some would say) and that would allow anyone to just paste their DID string there and that would refer to something.
There are a gazillion of different DID “methods”, most of them are probably barely used. What does it mean for an application to “support” DIDs, then? For the interoperability argument to make any sense that must mean that the application must understand all the “methods” – which involves understanding all cryptographic protocols and reading and interpreting data from a gazillion different blockchains and also understanding the specifics of each method, since the data of each blockchain or website and so on must also be interpreted according to the rules of the method.
It must be clear from the paragraph above that the DID goal is is unimplementable and therefore will either fail horribly by lack of adoption; or it will have to be changed to something else (for example everybody will start accepting just
did:key and ignore others and that will be the standard); or it will become a centralized thing with all supporting applications using a single set of libraries that have built-in support for all methods by calling centralized servers that return the final product of processing the DID data for each method.