What do you think the distinction between market making and trading is?

Also, yes market makers can get left with bad positions if the market moves against them, but when I was in the industry operational failures were the much more troubling issues.

I think MM doesn't take sides and try to balance the book while making a lot of pennies from both sides. However I heard (not in industry) that many MM are actively taking sides so the question.

Most market making strategies are run by firms that have a portfolio of other strategies that will be directional. Those mm strats, besides making the spread when possible, also allow the firm to maintain fee structures which make other strats possible and order inventory that allows them to have priority in the market. Most of the time the overall firm is mostly neutral while individual strategies/desks are directional.

All of its trading though and none of this is new.

Thanks! This makes a lot of sense~