It seems collective.twitter.action, which also wants to have collective.twitter.accounts. Things to watch out for:
- make sure you type collective.twitter.action, not collective.action.twitter. The last one is the old version, which does not support oauth
- I had to add plone.app.z3cform to the zcml section. See http://comments.gmane.org/gmane.comp.web.zope.plone.user/116535
Other then that easy: install collective.twitter.accounts, leave everything open, click on the 'get token' button, login and authorize. Then add your content rule. Works!