For a user profile property that comes from an external system, you need to map the property for a specific attribute of the external system. The default will offer some user profile properties mapping. You will only be able to map a profile property to an attribute with data that is compatible with the data type of property. You aren’t going to be able to map SPS-HireDate user profile property to the homePhone Active Directory. This is because SPS-HireDate is a date and HomePhone is a Unicode string.
For synchronizing profile information and importing profile properties from external systems you will be able to write data back to a directory service. You won’t be able to write data back to a business system. By mapping the property and setting the direction of it to export, you can indicate to SharePoint Server that you wish to export a user profile property.
Each of the properties will be mapped in only one direction. You can’t do both an export and import for the same user profile property. The data to be exported will overwrite any values that are already in place in the directory service. This is also the case for multi-value properties. The export value will always override them, not add to them.
With SharePoint Server, the groups are synchronized with user profiles by default. You will have the option to turn that function off from the Configure Synchronization Settings page. This is located in Central Administration. It is important to note that synchronizing groups is only supported in AD DS.
When you synchronize groups as well as users, the information will have to be imported for the groups that the members are part of in SharePoint Server. When a group is synchronized, it doesn’t create a profile for the group. It won’t allow any additional user profiles to be created. The groups will only be used to create an audience and to display membership for a visitor when it is in common with the person that the My Site belongs too in SharePoint Server.
If you are going to synchronized groups, you have to import information for all of the existing groups in the directory service containers with SharePoint Server. The exception is if you decide use a filter to exclude certain groups. The filter for excluding them is different from the filter for excluding users though, even though they do have a similar format.