I am planning to develop app which will integrate into facebook account of user and act as agent. The task of agent is to listen user account and how welcome message for users. If viewer is logged in then it will display message like welcome John otherwise it will display message like welcome guest.
Someone told me that it is illegal to write on user account page. But, I can check it further or u can guide me better.
I am not looking for exact answer but I need guideline.
Please guide me if it is possible.