Profile is a option which will change the way of 
application running we can set the profile value at 4 level

1. Site level 
2. Responsibility level
3. Application level
4. User level

User level is top most level 

1.SITE : If we set the profile at site level that will 
applicable all the user

2.RESPONSIBILITY : If we set the profile value as 
responsibility that will applicable to the users who are 
having access to the specific responsibility. If user 
having access to site,application and responsibility then 
responsibility will overwrite the site and application

3.APPLICATION : If we set the profile value as application 
to the user who are having access to that specific 
application if user having both access to site and 
application level then application overwrite site level 

4.USER : User is a top most level. If we set profile value 
if user having access to site, application, responsibility 
and user then user will overwrite site, application and 
responsibility

thanx
mstapps