Hope everyone is doing well.  Had two quick questions about chatter that I could use some help with.

1.  How do I customize the chatter name from the drop down menu in the top right of the screen.  For instance instead of salesforce chatter, I would like it to say "my company: chatter? 

2.  I cant get the salesforce chatter link to show up for my users.  Admins can do it but when they go to that menu, all they have is sales, call center, etc.  Any ideas?

I appreciate the help