I feel ColdFusion isn't used widely. What advantages does ColdFusion have? I've used PHP and Java to develop website. I wonder when and why we should use ColdFusion.
coldfusion offers a good deal of nice features like creating flash forms (they look cool), easy creation of pdf and flashpaper output, easy integration with Rich Internet Applications like Flex / AIR. Besides Coldfusion itself is a fully compliant J2EE application which means you can leverage all that stuff a J2EE application can do.
For me, Coldfusion is power with ease.
Like a few other technologies, Coldfusion has become like a swiss army knife for me.
ColdFusion is the easiest and quickest to learn to get meaningful results as well as it provides the largest cost-savings when doing any type of web development.