Poetry is an individual's creative written response to an experience. The experience may be physical, intellectual, or emotional. The poem may be one's personal response to something external such as a sunset; it may be a response to something internal such as love or grief or anger; or it may even be a response to an experience such as what it feels like to play an instrument on stage for the first time.
Poetry can be rhymed or unrhymed, have few or many lines or verses,
may contain figures of speech or not. It may follow a predetermined poetic form or be free form. It may describe images colorfully or starkly. The poem is the poet's canvas to express himself as he pleases. Lines of poetry may be interpreted in different ways depending upon the experiences the reader brings to it.
Poetry is a song that doens't have a limit. Grammar, spelling, rhythm, rhyme: doesn't matter. Poetry is essentially getting your ideas/feelings onto paper or recorded.
I think poetry is the soul coming into words. It's not about the human writing, but about the mind of the inner being coming alive. It's a story within itself, yet everyone absorbs different aspects of it in their own individual way.