I recently ran across a great article on CIO magazine on Software as a Service (SaaS) usage statistics by application and by industry. Although the numbers behind the chart probably come from a more enterprise-centric sampling of companies, I think they are interesting and are probably a good indicator on some of the types of applications and markets SaaS platform providers should be focusing on. Gartner estimates that in 2005, 5% of all business software spending was for applications delivered using a Software as a Service (SaaS) model and it rightfully expected the figure to grow to 25% by 2011. Their most recent projections saw the worldwide SaaS market reached $6.3 billion in 2006 and forecasted it growing to $19.3 billion by the end of 2011.