I think it was impossible to tell from the evidence. It basically came down to he said she said, and when one of the parties has a bad reputation and history of lying, there is just no way to know.
I think the sad thing is is that the accuser and his mother could be trying to extort money, but at the same time Jackson could have molested the kid too.
A likely scenario could have been that this woman put her son in this situation in the hopes michael would molest him and then she could get money out of him. Unfortunately for her and the kid, the jury saw them as more evil than Jackson.