I am new to Salesforce1. Having watched a few webinars, I am confused on whether it is mandatory to have Chatter enabled in order to use Salesforce1. Can someone please clarify what is the dependency of Salesforce1 with respect to Chatter?
Chatter should be enabled for using the Chatter feed, Groups, People and publisher actions in the Salesforce1 app. You can still use Salesforce1 to access Contacts, Accounts etc. (as well as perform CRUD operations on these objects) irrespective of whether Chatter is enabled or not. Again, integrating external apps via Canvas do not have any dependency on Chatter being enabled or disabled and would work irrespective of that.
This link provides information on which Salesforce1 features are dependent on Chatter being enabled.