The time between half-innings increases, so the radio and TV could play commercials on the broadcast. Pitching changes are longer, etc. You don't see it much at the game, but if you are one of the folks who used to listen to the game on the radio, at the game itself, you get a feel for how the flow of the game is affected by the broadcasts.
I haven't paid enough attention at baseball games. At hockey games, if you can see the scorekeeper, they have a lamp at the glass that will come on during a stopage to let the refs know it's time for a commercial (if you watch for this, you can get a jump on the crowd if you need a bathroom break or refreshments). You can usually predict a commercial timeout, they've got guidelines that are pretty consistently applied [1]
I meant to also say that the light doesn't go off until the commercial break is done, so they don't drop the puck before the broadcasters are ready. Typically an off-ice official holds a door open and stands in it to also signal not to start, if it looks like everyone is ready to go a bit early.
Not during batting. For pitching changes they do and pitching changes are more frequent now that starters “only” pitch 100 pitches or less. Time between innings seems to have a higher ad load though it’s inconsistent from what I can tell depending perhaps on the market.
