This question is a follow-up on a comment at a [recent question](https://academia.stackexchange.com/questions/1836/when-does-one-go-for-a-double-doctorate), where Dave Clarke mentioned that an acquaintance of his has "3 professorships and 2 doctorates". 

- How does a faculty member get appointed simultaneously by two or more universities? Are all except one honorary posts?
- Can any faculty member work with a second university with the consent of his present employer? What are the conflicts of interests that come into play usually?