in my opinion, those are things that are mainly used in the pen pal world and less so in the mail art world though some are similar to add and passes. a slam is a booklet that has a series of questions in it. it gets passed/sent around and each participant adds their own answer to them. there's also a version of a slam where you are to just sign a page if what is written on it is true for you (ie "been divorced", "have a sister", "been to nyc").  i think tags are just decorated tags(like a name tag or something), labels refers to address labels. bags refer to either a label bag or a goody bag. usually you put some of your labels in and when it's sent to the next person they will add some and take some out. the idea being you can make people decos or slams with the labels. goody bags function in the same way with stickers etc. but as a friend once said "it's just an excuse to get rid of all the ugly crap you don't want".