Using frameworks such as grails one can very quickly develop the server side of such web applications. With minor tweaks, a grails app can be exposed through REST controllers. These REST web services can be consumed by a variety of user interfaces like native mobile platforms, mobile web applications, single page thin client apps, HTML5 based web apps, etc. These user interfaces can also be integrated into portals such a Liferay, to complete the enterprise applications picture.
The above mentioned technologies and frameworks, relevant for rapid development of web and mobile applications, have been captured in the slide below. I will be periodically updating these slides, to raise awareness about contemporary frameworks that can be used for rapid web applications development.
(Note: this is just one good combination of frameworks with several alternatives on the tech landscape, like Play instead of Grails, etc)