Self-Organization is of growing importance for large distributed computing systems. In these systems, a central control and manual management is exceedingly difficult or even impossible. Emergence is widely recognized as the core principle behind self-organization. Therefore the idea to use both principles to control and organize large-scale distributed systems is very attractive and not so far off. Yet there are many open questions about emergence and self-organization, ranging from a clear definition and scientific understanding to the possible applications in engineering and technology, including the limitations of both concepts. Self-organizing systems with emergent properties are highly desirable, but also very challenging. We pose ten central questions about emergence, give preliminary answers, and identify four basic limits of self-organization: a size limit, a place limit, a complexity limit and finally a combinatorial limit.