Salesforce1 was launched with Dreamforce 2013 and provides mobile access to Salesforce data and standard functionality including standard and custom objects, reports, dashboards, and chatter. In addition to this, Salesforce1 is a mobile application development platform that allows existing functionality to be extended and entirely new applications to be developed.
The Salesforce1 platform supports Visualforce in the following ways - note that in all cases the page must have the Available for Salesforce mobile apps and Lightning Pages checkbox selected:
Embedded in page layouts: Using the same mechanism as the standard UI, the Visualforce page must extend the Standard Controller for the
sObject
typeLeft Navigation Menu: Visualforce tabs may be added directly to the menu
Publisher Actions: Visualforce pages may be surfaced as publisher actions on record home pages as long as they extend the Standard Controller for the
sObject
typeMobile Cards: Displayed on the related information...