It's when you see something written down that's not supposed to be poetry but has some kind of resonance for you. I often look at some little piece of writing...
"Everything must go"
"Keep out of the reach of children"
...and think it has hidden messages.
It's alright, I'm not schizophrenic, I'm a poet.
There are a couple of nice examples on Wikipedia, including this taken from pieces of text in "An Elementary Treatise on Mechanics":
Hence no force, however great,
can stretch a cord, however fine,
into a horizontal line
which is accurately straight.
My poem uses phrases taken from my certificates of birth, marriage and....
...divorce (hands up who thought I was going to get all spooky and say 'death'?)
I'm in two minds about some of the other poems in this publication which make new poems from phrases in other people's existing ones... which seems a bit cheaty to me.
So, just out of interest, why don't you look around you for phrases in instructions, manuals, signs, magazines, begging letters, sermons and statute books... and put your mini 'found' poem in the comments?