Apps vs. Solutions
An app for SharePoint is a stand-alone, self-contained piece of functionality that extends the features and capabilities of a SharePoint site. Apps can bring together the best of both worlds; modern web technologies and all the familiar pieces of SharePoint. On top of that, users can discover and download apps on their own from the public Office Store or from their organization’s private App Catalog. In contrast, a solution is used to customize or enhance SharePoint sites and needs a farm administrator to deploy, manage and remove.
The first question that I asked myself was why would you use an app? I would assume that the answer to this question might depend on who you polled, but as a developer, I am extremely excited that I can now leverage all of the exciting things that my “non-SharePoint” counterparts have been doing for quite some time. In my opinion, this paradigm shift is a smart move by Microsoft, and will go a long way in attracting more developers to the platform.