This is a commonly asked question;
What is RPGing/an RPG?
RPG is a term used that means, 'Role Play Game', and RPGing is when you play as a character that is not the actual you. Kids often do this when they play around, pretending to be horses, dogs, Albert Einstien, or whatever. An RPG is often in the form of a Forum, or a video game.
There are also other forms of rpgs: MMORPGs. That term just means a Massive Multiplayer Role Play Game. Ever heard of Wizard101? That's a good example of an MMORPG. What about ToonTown? Yes, it's also a MMORPG. These are only two examples of rpgs that let you be with new friends, or old ones.