The quality of the piece is but one of those reasons, making it very difficult for new writers. There are no taboos so long as the material is treated with balance and taste. I am particularly interested in humor pieces. In general, partisan political pieces and aggressively religious material turns me off. Three or four 1000 - 8000 word stories, no horror or porn.
Eroticism is ok if it is appropriate in the larger context of a good story.
Good characters are a must. Most of the people I know have to like someone in a story in order to continue reading. If life sucks and you want everyone to know it, there are probably better places to send your stuff than to me. I like poetry that illuminates the human condition, stirs my sense of wonder, leaves me at least as whole as it found me. Aside from that, I'm open to all forms, all subjects.