We work in a 3 person team max, and run a project management tool/CRM next to it (apollo) so there is no need to do communication via special protocols. We tried a bunch of them and it just doesn't work for small teams. We live in GIT anyway, so a todo.txt is a really good solution.

It's mostly: email to say bugs need fixing -> bugs get fixed -> fix gets committed and the bug removed from the todo -> email back that it's fixed.

It mostly concerns visual (html/css/templating) bugs or small js bugs that don't have unit tests/