Of all the people in MD you should try to meet, get in touch with a girl called Handy Pockets.
She can normally be found at Awiiya's Way (Another interesting fellow, but he may confuse you for a while ), which is just inside the MDA Gates (Have fun trying to find that, it isn't too hard )
After that, look for Mya Celestia, she hangs out around the Paper Cabin and Marble Dale Park, when she isn't in Loreroot.
Sagewoman and Windy are also great people to chat with, if you can find them (They have had RL issues to deal with right now, and have not been on as much)
If you can get them to talk, Grido, Shadowseeker, Metal Bunny, Tarquinus, Yrthilian, and Burns (who is actually rather talkative) are some of the more interesting Men around the realm.
A few other friendly faces are Manda, BFH, nadrolski, myself (Kyphis), Curiose, Innocence (Although she will confuse you), Pamplemousse, dst... well, basically almost anyone who communicates back with you
Far as talking to people though...
You can get a lot of useful information from the [Players in Location] List above the chat. Golden names are those there right now (although not necessarily awake - more on that shortly), grey names are those who where there recently but have either moved location or logged out. If the name has a coloured picture on its left, they are part of an alliance, and if they have an * before and after their name, it means they are an LHO (and thus, especially friendly and helpful).
Sometimes, when you click on the name of someone who the location list shows as golden, above the players name it will say ~~ Idle ~~. This means that the person is not really there, but they have gone Idle (as opposed to logging out) so that people can either fight them, leave them messages, read their papers (you will learn about these as you play, just ask in chat), or write on their PL.
Basically, just like a real world social group, there is a lot of things going on and that you can do, most of which you will pick up very quickly as you go along.
Just don't worry too much when you get locked up in the story, that is only a very short section and you will be back out in the world very quickly.