In Windows 8 some of the applications delivered using windows store app. In windows store app we can use publically available apps and also we can add internally developed application (What we call Line Of Business (LOB) apps) to Windows using various methods.
By default, when an application is opened using windows store app, the opened application fills the entire screen to reduce distractions and simplify the user experience. Windows Store apps can support different layouts and views, such as landscape, portrait, and snapped.
When windows 8 is used for enterprise users, we can deploy LOB apps using Windows Store or Sideloading.
Windows Store: If we want to target wider user base both inside and outside of the organization, list the app in the Windows Store.
Sideloading: When we want to target users within the organization, we can sideload the apps. Sideloading allows the organisation to distribute directly to the users inside the organization. When we sideloade the app, the sideloading bypasses the validation and signing requirements of the Windows Store.