[r3bl]

Both terms are just stupid.

Deep web: stuff not indexed by search engines. Private forums, non-public social media accounts, Telegram rooms, Discord servers etc. are technically "deep web".

Dark web: a subset of deep web that requires specific software or configuration to access. Slightly more precise, but still includes every possible use case for IPFS, Dat, ".onion" etc. Note that this is nowhere close to what people usually mean when they use the term "dark web". They're referring to the subset of a subset of deep web that's used for criminal activities.

[rendx]

There are gateways to onion services and IPFS, so those are "indexed by search engines" without any change necessary. Furthermore, any search engine has to be adapted to the medium used, and there are specialized search engines for pretty much anything including Freenet and I2P etc, so saying that the "dark web" is a subset of the "deep web" is incorrect. There is some overlap, but it's not a "part of" relationship.

The problem is that there is one (academic) definition of "deep web", but many incompatible definitions of "dark web", invented by the media basically for whatever they want it to be.