Multiplayer is a very fun way to play Minecraft. There are very different kinds of mulitplayer servers which can make multiplayer very confusing. The main idea of multiplayer though is to play with other players accross the world and chat with them.
Types Of multiplayer
Creative - just building no dying possible Survival - Survival with health points and hunger bar
PVP - Player vs players, murdering, stealing, allowed. PVE - Player vs enviorment, normal survival with extra MOBs RPG - Roll Playing (medieval times theme, or cities theme ect.) Vanilla - With Mods Free Player - No Supervision or rules Whitelist - must be approved before joining
Cracked Server -anyone can play, playable on Minecraft For Free Server - Normal version, you must have premium account to play
making a server
I'm not exactly sure how you make a server but try google. I don't believe though that it costs anything to make a cracked server, and if you make a server (not cracked) the only cost is your premium account.
I am thinking of making a cracked server for this site... it would be probably PVP with a Hunger Games theme... i will keep you updated.
How to get on to one
Servers can be a little confusing at times to find and use. Most cracked servers require you to login at there site or you won't be able to move when you spawn in.
When you click Join Server you ussually end up spawning in a lobby of somesort that the Server Master has built purposley for new joiners to spawn in. If you are unsure of what to do look around for signs that can help you or ask a moderator.