If I'm writing a hobby project, I want it to help the ecosystem as much as possible. If businesses want to use it then great! So MIT.
If I'm running a business my main goal is to survive. I want to help the community as well, but I obviously can't do that if I go broke. "Put on your own oxygen mask before helping others" and all that. So *GPL, because it lets me balance those goals.
Personally, if I'm writing a hobby project then I want it to be copyleft. Of course I want it to be copyleft. Why wouldn't I? I don't want some company taking my work, making proprietary changes and improvements to it and then not releasing those back to me. Copyleft is simple courtesy that you'd expect anyway, codified into a license.
> Personally, if I'm writing a hobby project then I want it to be copyleft.
Totally up to you! In the context of Haskell projects though, I really, really want to see Haskell businesses succeed as well as the open Haskell ecosystem.
BSD and GPL are both free, libre and open.
>Totally up to you! In the context of Haskell projects though, I really, really want to see Haskell businesses succeed as well as the open Haskell ecosystem.
There's nothing about the GPL (or other copyleft licenses) that makes them incompatible with business.