[jacobharris]

There are a few awkwardness checks we do that disqualify some haikus. For instance, if the second or third line has a comma right near the front or back, or if there are month or title abbreviations, etc. But I'm always looking to refine it further.

[sthatipamala]

It would be nice if lines didn't end with prepositions or determiners (http://en.wikipedia.org/wiki/English_determiners). Those words depend on whatever follows, so it causes an awkward split. It shouldn't be hard to add such a check.