One of the defining aspects of the Metaverse is its capacity to connect economies, assets, avatars, systems etc across many different spaces and environments. This idea is commonly known as Interoperability.
People often confuse one area of interoperability with another, adding to the confusion in how they think about challenges and opportunities. When it comes to the Metaverse we can look at interoperability through different lenses (domains).

Domains of Interoperability in the Metaverse
The connectivity level deals with the ability for various devices to communicate with one another. TCP/IP, ethernet, mobile network standards, HTTP for websites, and other technologies have essentially solved this problem.
We already have significant degrees of interoperability at this level. It is one of the reasons why the Metaverse is referred to as the next generation of the internet, rather than just one type of product within the internet.
The Persistence level deals with the process of storing the state and identifying attributes of a digital asset. There are two main ways this can be done - one is through a central database owned by a company and the other is via a decentralised storage system such as those created by blockchains and is not controlled by any company.
The Presentation level deals with how things will appear and be presented in the Metaverse. Will things be low-fi and voxel-based like Minecraft or The Sandbox? Photorealistic like Unreal's MetaHumans? Or something in between? The challenges of the Presentation level aren't really around the technologies: they're around aesthetics and accessibility.