What role does this person play?
They are responsible for the site that you are using and your first line of defense.
What do they have access to?
They have access to “everything” on the entire site collection. Even though you can’t see their name in the permisisons, they are there to help with any problems. Make sure that this role is limited to only a few people.
What if I don’t have access to something in SharePoint?
Site Collection Admin will get an email and be notified that the person logged on needs access and they have a space for you to write a description.
What else can they do?
They can access the Site Settings page and help with all the functions and features that come with your platform. Depending on what SharePoint product you purchased and if it is Enterprise based will also be determining factors.
Are there classes and training for this role?
There many resources and training for SharePoint roles. Depending on the company you use for training, often times you can tailor your training to roles in your SharePoint envirnoment.