Services user/login and system/connect I would like to know the difference between user/login and system/connect.
system/connect


  Returns the details of currently logged in user.


user/login


  Login a user for a new session


To login a user you will use user/login service call... Once user is logged in if you would like to pull logged in user details you will use system/connect service.. You can see above details in services module help section