I used the first link and dumped in about 3,300 words I'd written for a fiction story before, and got INTP. Interesting.
Introverted iNtuitive Thinking Perceiving
INTPs are quiet, thoughtful, analytical individuals who don't mind spending long periods of time on their own, working through problems and forming solutions. INTPs tend to be less at ease in social situations and the 'caring professions,' although they enjoy the company of those who share their interests. They also tend to be impatient with the bureaucracy, rigid hierarchies, and politics prevalent in many professions, preferring to work informally with others as equals. INTPs' extraverted intuition often gives them a quick wit, especially with language, and they can defuse the tension in gatherings by comical observations and references. They can be charming, even in their quiet reserve, and are sometimes surprised by the high esteem in which their friends and colleagues hold them.
Edit: To switch things up, the second time I used a poem, got ENFP. My Big 5 scores went up to 97% Liberal and Artistic, and whereas I had a slight preference, 13% for Competitive the first time, it went all the way to 88% Team working and Trusting for the second. I think I've taken similar tests before, and seen similar differences depending on the nature of the text you input.