Anyone know why Sarah Palin has resigned?

Here are the words of William Kristol:

William Kristol,
the editor of The Weekly Standard and a supporter of Ms. Palin, said
that in the end, this could turn out to have been a smart move.

“Everybody
I’ve talked to thinks it’s a little crazy,” Mr. Kristol said. “But
maybe not. What is she going to accomplish in the next year as
governor? Every time she left the state she got criticized for
neglecting her duties.”

“She’ll take a little hit for leaving the
job early, no question about it,” he said. “But if she writes this book
and gives speeches and travels the country and educates herself on some
issues, that’s good.”