A KB article on the adobe site refers to a virtual cookie stating "Each visit is assigned a visit number, based on a virtual cookie" http://helpx.adobe.com/analytics/kb/comparing-return-visits.html
While I know what 1st party and 3rd party cookie is. Can someone please help me with what a virtual cookie is?
Since this is an older post, I'm assuming you've solved this issue. Incase others find this post, I'll post the link to the documentation below