Software as a Service. Refers to software which works under the model of the user paying to use the software instead of the traditional model of paying for owning the software (or owning a license for it). Typically SaaS is used for software packages which are run across the internet.
软件即服务。不同于传统的购买软件、或购买软件授权的模式，它倾向于用户付费使用软件，用软件提供商提供服务。典型的SaaS一般被用于互联网。
出处：http://www.cryer.co.uk/glossary/s/saas.htm
参考：
http://www.hrbhzw.com/html/20073/info_cci_2066.html
http://www.enet.com.cn/article/2007/0405/A20070405524827.shtml