server  - always on host  - permanent ip address  clients:  - communicate with server - may be intermittently connected  - may have dynamic ip addresses
server: -always on host -permanent ip address -scaling by data centers clients: -communicates with server -do not communicate directly with each other
abstracting data to provide info in a visual format -enhance user's ability to efficiently comprehend the meaning of data  -pie/bar charts -heat map -gantt chart -line graphs -scatter plots