I was reading about an online literary magazine today and their submission rules include a demand that work has never been published before, not even on your own blog. Ridiculous. That’s like saying you can’t win a cookery competition if you have cooked a dish for someone in the past and they have eaten it.
Blogs are a modern version of the type-written page. By this criteria they would have excluded work in the past which had been read by anyone but the writer. Idiotic. Luckily I rarely submit and so don’t care but struck by the stupidity of it.