There's a couple different categories of pins, if you will
Mostly people talk about pins for pin trading - these are the nice enamel and metal pins that you can get at the Disney store or in the parks. People get lanyards to place them on and you can trade them with fellow park attendees or cast members.
That is the official Disney Pin Trading website and it has a lot of great information, including basic "rules" of pin trading and such.
there is also an entire message board for pins: www.dizpins.com and the people there are really nice and you can learn a lot from poking around on there.
If you are celebrating a special occasion, such as a birthday, anniversary or first ever trip to the world, guest relations has button-style pins that are available for the asking (some resorts seem to have them at check in as well)
I have been taken in by the addiction!
1st they were supposed to be my DS6's, that way he had some to start out with, he's really excited, but....... I had to have every single bride type pin I could find.
This is my ds8 newest obsession. He paid attention to more people this trip and first noticed the trading in the arcade. After a discussion with a cast member he had to have pins and a lanyard and started trading right away. This was good for DS as it brought him out of his shell a little more.(very shy)
Not so good for our wallet as he is OCD and can't get enough of the pins!!
My DS (3 1/2) would not trade and I bought him a Buzz starter kit, so he has two sets of the the same two buzz pins, plus one more cool castle one my dad bought. He kept saying, "I am not ready to trade!".
ah.....pins.......addiction? NEVER!! I've been a pin collector for just under 1 year now and I have about 530 pins in my collection.......mind you I started out with about 25 that I bought to trade.........yeah........well there goes my checkbook!
I've been collecting and trading pins for about 5 years. It truly is an obession. Mr.Ebay and I are very friendly! LOL Anyone you see in the parks with a lanyard is usually either a pin collector or a trader. Any cast member with a lanyard will trade with you. Just note that the green lanyards are for kids only. If you want some starter pins to trade you might want to check out Ebay's Disney Pin Lots. You can usually get pins at a very resonable price! Then trade for all your favorite when you get to the parks.
We missed the boat the first 5 days we were in the World....DD didn't think anything about the pins till she saw a ballerina minnie mouse. Then of course she had to have enough to fill up her lanyard! I am planning on getting some off of ebay before our next trip!