It's a very loose definition -- publications that publish daily with loyal readers, that have the liklihood of generating triple-digit reads and new followers. They also frequently auto-curate. :-) The ones I have targeted include: The Startup, The Writing Cooperative, Entrepreneur's Handbook, Mind Cafe, Curious, Publishous, In Fitness and In Health, Better Advice, Better Humans, and Know Thyself Heal Thyself. There are others, certainly, but these are the ones that seem like the best fit for me. I've written for 4 of them already, and would like to get into the other 6.