Many enterprises are considering information and knowledge management (I&KM) software-as-a-service (SaaS) solutions as alternatives to on-premise software installations and perpetual-license models. In response, I&KM vendors — old and new — have launched more than 100 SaaS offerings. But what software categories should I&KM professionals focus on, and which ones are likely to be generally adopted? To find out, we developed a "SaaS-ability" model indicating how well SaaS delivery works for a category. The most SaaS-able I&KM apps are blogs, email, and Web conferencing, while the least SaaS-able are business process management and master data management. You can apply this framework to other categories or your own applications to determine if SaaS is a viable option for your organization.