How will TASTy affect the Scala ecosystem, exactly?

We have all been hearing the promise that TASTy will "solve" the problem of binary compatibility in Scala. But what does that mean, exactly? What problems are we talking about, and how will TASTy solve this problems?

In this talk, I will cover everything there is to know about how TASTy will affect our ecosystem: what it means for compatibility across versions of Scala (Scala 2 to 3, but also 3.0 to 3.1); across versions of a given library; what it means for our tools such as MiMa.