Just a small note on the shot-scraper post (very cool stuff!): You can use Array.from(xs, fn) instead of Array.from(xs).map(fn). Same semantics but it happens in one pass with less garbage.
Mission Bit doesn't have permanent classrooms. All of the equipment needs to be portable and standalone, so laptops are a requirement. Small HDMI computers such as Raspberry Pi are no longer cheap once you start looking at adding a keyboard, mouse and display.
We standardize on Mac to keep the experience as uniform as possible. A huge issue that few people consider is that if you have a fleet of mismatched laptops you're going to spend a lot of time and/or storage space sorting out which power supply goes to what and it's going to take a lot longer to build a single image that's going to work well for all of them (regardless of OS).
We're doing a pilot class with Chromebooks this semester, but we have to buy most of those ourselves. We've found that it's often easier to get a donation of an old Mac laptop than ~$220.
I found Erlang a lot easier to learn than Haskell. I don't really find them to be very similar, especially because they have a completely different evaluation strategy. The syntax and semantics are also quite different. Specifically, Haskell's non-strict (lazy) evaluation turns everything inside out so you tend to write many things in a different way than you would in Erlang.
Erlang requires a fair amount of boilerplate for a small project (rebar, app file, application behaviour, gen_server behaviour, etc.) and escript doesn't work very well.
It lacks a good way to do abstract data types (records don't count).
The compiler's ability to optimize is limited by the lack of purely functional guarantees and the metaprogramming facilities (parse transforms) aren't easy to use to work around that.
There's no facility like Haskell's ST or clojure transients to encapsulate mutable stuff, just a hole to write code in C and who really wants to do that? Yes, I know about the process dictionary and ets but those aren't appropriate for most algorithms I've wanted mutability for.
That said, I still use Erlang, but only in the domains where it really shines.
Sadly it's not possible to have CouchDB make that happen for you! You can very easily allow unauthenticated requests to create users, but there's no way to create those per-user databases without writing some trusted code that runs separately from CouchDB.
Jameson and I spent Mochi's first summer (2005) on Maui, where we built the majority of MochiBot and MochiKit. Worked great for us, although we didn't keep California time or do any planking.