You can search your contact lists for contacts belonging to a particular domain. This is of course useful should you just want to find contacts belonging to a particular company, for instance.
Finding contacts belonging to a particular domain
Select Contacts from the navigation bar and then select the All contacts address book (or any address book):
At the top of the screen is the 'Quick search' tool:
This can be used to find a contact or contacts by email address or domain. To find contacts by domain, simply type in the domain and click on the magnifying glass icon:
Contacts matching the criteria are then displayed in the list as your search's results. This will only match based on the email address, and not on any of the other contact data fields.