[@MissFlick] I definitely go for quantity because it's easier to fathom.

With this kinda comes the expectation that longer posts are also better quality but that isn't always true, so be careful with that. In general, I find the '2 paragraph' rule for advanced silly because advanced writers typically write much much more.

If anything ask yourself 'how invested am I' and if the answer is 'eh, I just want to do 1 afternoon of quick back and forth' it's probably free, if the answer is 'I want to reply back and forth every day but with more to read, more to write and generally not as fast' then it's probably casual and if it's 'I sometimes take a month to write a reply, but it's often really long and well thought out, edited multiple times and then spellchecked by two professors that teach English' then it's probably advanced.