I haven't quite bottomed out the problem yet, but Newsticker seems to have problems with Javascript optmization.

Specifically, if the module is enabled on a site with "Optimize Javascript files" set to "On" (Admin->Performance), the newsticker only works if the user is logged in.

Not a big deal for me, as testing suggests the performance gains from activating this are fairly minor.

Great module, btw. Very easy to theme. See here for theming using a derivative of Acquia Marina:

http://www.reachinsurance.co.uk/