Sometimes when I want to step outside of my own concerns and conventions, collaborative writing can open up new ideas. The oldest poetry was collaborative. There was no "Homer." Rather, Homer was a series of poets who memorized and revised the hymns and epics. New language was added; portions were lost. What remains is the effort of not a single poet but a community. I imagine even the whims of the audiences helped shape the poems.
A collaboration is a kind of relationship. When the writers are listening to one another, bringing seriousness, honesty and a healthy dose of play to the work, it can feel wonderfully alive. And if the collaboration isn't working, one or the other should recognize that and have the good sense to talk about it.
I've co-written with some wonderful writers: Rachel Zucker, Mark Bibbins, David Trinidad and Jeffery Conway, Luke Sykora, Ryan Courtwright and T.J. DiFrancesco. Each of them delightful to work with; each of them willing to discard the chaff (whether mine or theirs or both) and to concentrate on the serious play of writing.
Recently, David Trinidad and I finished a short chapbook, a memoir constructed out of sentences from other people's memoirs. I'm very proud of the result--which shows how much a good partner in rhyme matters--and Turtle Point Press has done a beautiful job of designing it and printing it.
It's so satisfying to work with a fellow poet when you feel that poet feeds the creativity. I've had other experiences with collaborators (not the ones mentioned above) where they just wanted credit for showing up. Some of those poems turned out fine anyway. But it's so much nicer to work with the poets who surprise, delight and challenge us to be at our 'A' game.