They are charging for baggage on Econo only, which sells out stupid quick and don't make up a large portion of seats. So if you book Flex or Plus, you either get one free bag or two free bags. They are also changing their reward structure, so people who actually travel a decent amount are going to get 5% back on airfare now after they hit $3000/yr spending.
The people who are blowing up Twitter are the ones who travel maybe once a year, don't use the reward programs and don't know how to maximize value. They are also probably taking 2 suitcases each for a family of 5 for a week long trip.
See Crank. See Crank Walk. Walk Crank Walk.