What is the difference between datapump and old import/exportilities in oracle?

Datapump is a server side utility where as export/import is a user process. Datapump improves the performance dramatically over old export/import utilities, because the datapump processes running on the server have direct access to the datafiles and the SGA. They dont have to go via session. Also it is possible to launch a datapump job and then detach from it, leaving it running in the background. you can reconnect to the job to monitor its progress at any time.