Who submits articles/posts to link farms? Marketing agencies?

Hello everyone. I tried posting earlier but it never appeared, and I think maybe it's because I included links. I'm curious if there's a way to know who's behind websites billing themselves as article submission sites and what types of organizations use them. An example is "topcontentcenter." There are dozens or perhaps hundreds of these websites posting massive numbers of unrelated articles with links to businesses in basically any category. I guess it's hard for me to imagine this is an effective SEO strategy anymore. I remember there used to be something called EZ Articles that was similar.