Marketing resources thread

so i posted in another thread about how it'd be good to have some kind of masterpost. this isn't it and probably shouldn't be, but it'd be good to start thinking about what kind of links or resources are the best things to put in it and listing some things now. here's a few that i think are particularly worth linking just shoved together just to get things rolling

to be honest that's all i've got at the moment that feels substantive. link services, tools, books, blogs or whatever in the comments so we've got a bunch more stuff.