Hey all I am currently making a tiered link structure. There are many link types (engines) and I dont know all of them. I know these: web 2.0 - mainly do-follow passing relevant link power. most important social bookmarking - mainly nofollow, speeding up the indexing and a signal of trust social profiles - signal of trust, not sure what else Thats what ive learned till now. However what these do? wiki article directory (like a single web 2.0 article without blog/profile that contain more of articles) forum profiles press google place pdf (usually programs im using fail on inserting a link in PDF so cant tell if its important) I really really want to know what links can/should I skip and which i shouldnt.