Here is IBM's explanation:
Computing as a service over the Internet
Cloud computing, often referred to as simply “the cloud,” is the delivery of on-demand computing resources—everything from applications to data centers—over the Internet on a pay-for-use basis.
which one is better? IBM clearly tells you at the very beginning that it is a 'service'. 你大概不会以为IBM也“缺乏基本的计算机知识”吧。