What is found and erasure poetry?

Found poems take existing texts and refashion them, reorder them, and present them as poems. The literary equivalent of a collage… A pure found poem consists exclusively of outside texts: the words of the poem remain as they were found, with few additions or omissions. Decisions of form, such as where to break a line, are left to the poet.

Erasure poetry, also known as blackout poetry, is a form of found poetry wherein a poet takes an existing text and erases, blacks out, or otherwise obscures a large portion of the text, creating a wholly new work from what remains.

(definitions of found and erasure from poets.org)