Duotrope's Digest is an excellent free writers resource which helps us find markets and manage our submissions. Whether you are an editor or writer, if you write prose or poetry Duotrope is an invaluable service.
Because it is free, however, they rely on our support in the form of donations and spreading the word. If you can't afford to give then why not follow them on Facebook or on Twitter. Or put a banner on your site. Anything to help spread the word.
If you don't know it, check it out and if you do, see what you can do to help.