  In the Metaverse, the physical space and the virtual space co-exist, and
interact simultaneously. While the physical space is virtually enhanced with
information, the virtual space is continuously refreshed with real-time,
real-world information. To allow users to process and manipulate information
seamlessly between the real and digital spaces, novel technologies must be
developed. These include smart interfaces, new augmented realities, efficient
storage and data management and dissemination techniques. In this paper, we
first discuss some promising co-space applications. These applications offer
opportunities that neither of the spaces can realize on its own. We then
discuss challenges. Finally, we discuss and envision what are likely to be
required from the database and system perspectives.
