So my first stop was their website, where a clear infographic of their team publishing model is easily accessible. Simply put, Booktrope vets books through a team of volunteer readers, then "pull[s] together a small, dedicated team and free[s] them up to do the best work possible." They are not a self-publisher or a vanity press, and they make the essentials (editing, design and publicity support) available to their authors at no cost.
Pretty cool concept. If you'd like to read more about Booktrope, check out their website or this article in Seattle Magazine.
My search turned up lots more info, but my ten minutes are up :-) Chances are you'll find more on the topic of hybrid publishing in future blogs.
Happy reading! (And congratulations, Lori!)