Good questions, thank you. Aqueduct initially started as a proof of concept - as a mobile shop, Dart was just so familiar to the languages we often used and it ran on the server. We tried building a few things and everyone was able to pick it up so quickly, and it took off internally from there. The value to us as mobile developers is that there was less context switching than when jumping into Ruby or JS (and all the other reasons we aren't quite fans of JS.)

Yes, multi-threading is accomplished through isolates. The application is run as a replica on a number of isolates, configurable by a command line option.

Each isolate has its own database connection, etc., but operate exactly the same. This behavior doesn't require any additional effort by the developer. (edit: The initialization code sets up a reactive channel for requests, each isolate instantiates that channel, and Dart's VM manages delivering an HTTP request to the most appropriate isolate.)

So, it's not quite like Erlang/Elixir where each connection gets its own process, rather the default number of isolates is 3. Isolates have their own heap, so memory isn't shared across them, but there is a message hub that isolates can send values across. This is useful when say you have websockets connected to different isolates and you want to broadcast a message to all of them.

You can spawn additional isolates from a 'web server isolate' to move computation to another thread.