There’s quite a few interoperability solutions right now. Here’s a list of projects I’m aware of:
What will be the first use case for these projects?
The short story is they’ll be able to transfer tokens from one blockchain to another.
Do we need these solutions for that?
Probably not, however, it’s too early to tell. As Kyle Samani pointed out, cross-chain atomic swaps will probably be done by 0x at some point in the future.
Ok. So where will the value occur in these systems?
When these projects have the ability to send actions from one smart contract on one platform to a smart contract on another platform, then they could be incredibly valuable. This is called, “remote smart contract method calls” for developers.
Here’s an example:
There’s value for performing that middleman function, despite it sounding boring!
Great! So how will that work in practicality?
Most likely users will have no idea they’re using one of these interoperability solutions. Token abstraction will take care of this at some point, meaning some fancy programming will allow users to pay fees using the token they already have instead of getting ten different tokens.
An example of token abstraction is ERC-865.
So who’s going to win?
ICON, Aion, and Wanchain formed an interoperability alliance to create standards to solve this problem, however, it’s still too early. Expect consolidation around a few solutions in 3–5 years.
Note — this is note financial advice. Just my opinion. Please perform your own due diligence before investing.