Wikipedia has a good article on the Haiku form- 5-7-5 gets taught in schools a lot but slavishly holding to a syllable count does not produce a haiku. The most important thing is the juxtaposition or twist which causes you to stop and think. Natalie Goldberg in Writing Down the Bones calls it "A Sensation of Space" - "If you read a lot of Haiku, you see there is a leap that happens, a moment where the poet makes a large jump and the reader's mind must catch up.". The Wikipedia article puts it this way "the subtle linkage or juxtaposition between the two sets of images within a haiku will be found to contain an interesting insight or spiritual message". Unfortunately it is rarely taught and leaves most Haiku wanting.

What you're speaking of isn't so much "what makes a Haiku", but "what makes a Haiku good". It is very common in poetry to follow all the rules and still suck.

The things you quote and say about good haiku apply to pretty much any art form -- the ability to move the reader is so much more important than the ability to follow the rules strictly. However, like with most arts, you should learn to follow the rules well before you break them. It's like use warnings; -- there are appropriate times to turn it off, but it is rare and only done when one has already understood how to work supremely well with it on. In poetry and in code, you follow the rules until what you want to accomplish necessitates bending or breaking them.

Anima Legato
.oO all things connect through the motion of the mind