[elviejo]

I'm in the same boat. I've been looking at this space since (P)NaCL With a nagging question in my mind:

What does this do that we couldn't do with Java Applets? So far the response is very few things and a lot less. On the few things that it does differently is: + it focus on multi language support. as opposed to the JVM which was focused in getting all of us in writing Java. Here they want to actually use different languages to write webapps. - Although Rust is the favorite (As is C# in the .net) + It has a clear mechanism to communicate with Javascript and therefore the web. + timing bandwidth is now big enough to make this apps seem practical. + it is done by a coallition of vedors (as opposed to java that was only Sun's baby).

Very minor advantages in my opinion... but well I also think that lip's s-expressions are better than json, xml and yaml. and the world has thought differently every single time.

[marwis]

Security. Applets exposed massive API surface while wasm exposes almost nothing.

Also applets were too slow to start with Sun's implementation of the day while wasm works reasonably well in all browsers from day one. That matters a lot for adoption.

JVM improved but applets missed their chance. You only get one.

[mike_hearn]

WASM exposes nothing ... except the entire browser app surface.

WASI starts with nothing and then exposes a bit more. WASI2 exposes more than WASI1. Preview 3 will also add more. Eventually there will be sandbox escapes in WASM runtimes as well. There's nothing about WASM that makes sandbox escapes harder.

Bear in mind, applets exposed a large surface area, because you need that to write useful apps. Currently WASI looks useful for, maybe, some subset of CLI tools. Everything else is kicked to Chrome. It's not as ambitious.