Sites, lists, and libraries can be exported via Central Administration or Windows PowerShell. This method is intended for restoring items, or moving/copying items from one farm or another. You can import a site, list, or document library from a backup of the current farm, a backup of another farm, or from a read-only content database. However, imports can only be performed through Window PowerShell.
Another method, although more restrictive, is to save your SharePoint site, list, or library as a template, by creating a Web Solution Package that will get stored in the Solution Gallery for the SharePoint site collection. Note that this method is not supported for sites using the Publishing feature.