You can do a lot of cool things on there including becoming Rainbow Dash, Becoming a Puffle, Custom colored snowballs, sliding, walking on walls, ect.
It is really popular on Youtube since a lot of people make videos on there.
Penguin Oasis is the most active server. They always add an update like glitches, items, emotes, ect.
Come on Penguin Oasis and Join the Fun!