This is normal, and all cars actually do it.
In 99% of cases, water from your car exhaust system is absolutely normal and is nothing to worry about. It is just condensation being vented while the engine is running. You’re most likely to notice this when the outside temperature is cold and when the engine has not been running all that long.
This is what it is in fediverse. Multiple instances can have same communities.
If I’m looking lulz communities, I just subscribe to those with most users, because most likely it will be more active.
If I’m looking for tech or something useful, I subscribe to most of them, and then filter them after some time. Not all communities will fit your style, and you will have to choose with which community you are more compatible.