Does duotrope have any rivals?
There is Poets and Writers (www.pw.org not to be confused with writersandpoets.com which is self-publishing) and they have a huge listing of grants, awards, and contests for writers. But not in the way of a market listing as duotrope has.
Writer's Market does have a large market index, but it is not free...
Those two come to mind, but I'm sure there are more.
