Umbraco is an open-source content management system (CMS) platform for publishing content on the World Wide Web and intranets. It is written in C# and deployed on Microsoft based infrastructure. Since version 4.5, the whole system has been available under an MIT License.
Umbraco was developed by Niels Hartvig in 2000 and released as open source software in 2004. In 2009, CMS Wire described it as one of the leading .NET-based open source CMS systems. In 2010, with 1000 downloads a day, Umbraco was in the top five most popular downloads via the Microsoft Web Platform Installer, two places below its main rival DotNetNuke and was the 12th most downloaded application from Codeplex, six places below DotNetNuke and 13 places higher than mojoPortal.
Wikipedia - see full entry
A web page is Umbraco is built up in sections. The basic building block is the Page Section (puzzle piece icon).
A very useful content type is the Accordion Group which allows you to arrange content into a set of menus that open and close as you click on the menus.
The Responsive Image content type allows you to add an image that will resize smoothly according to the size of the screen of the device the site visitor is viewing the page with. The image spans the full width of the page.
