Seems she was rousing her Un-American base to act. The Secret Service puts the reason for the spike in threats against Obama as the hate spewed by Palin as she campaigned.

http://crooksandliars.com/david-neiwert/secret-service-blamed-palin-sudden-s

All of the talk about the special Newsweek report describing the backstage events in this year's presidential campaign has focused on various revelations about Sarah Palin's astonishing lack of knowledge about global and national affairs, as well as her spending sprees.

But this passage seemed at least as significant, if not more so:

The Obama campaign was provided with reports from the Secret Service showing a sharp and disturbing increase in threats to Obama in September and early October, at the same time that many crowds at Palin rallies became more frenzied. Michelle Obama was shaken by the vituperative crowds and the hot rhetoric from the GOP candidates. "Why would they try to make people hate us?" Michelle asked a top campaign aide.