Update your contacts with Twitter. Go to Settings > Twitter, then tap Update Contacts. Twitter
matches email addresses and phone numbers in order to add Twitter user names and photos to
your contact cards.
When you have contacts from multiple sources, you might have multiple entries for the same
person. To keep redundant contacts from appearing in your All Contacts list, contacts from
different sources that have the same name are linked and displayed as a single unified contact.
When you view a unified contact, the title Unified Info appears.
Unify contacts. If two entries for the same person aren't linked automatically, you can unify them
manually. Edit one of the contacts, tap Edit, then tap Link Contact and choose the other contact
entry to link to.
Linked contacts aren't merged. If you change or add information in a unified contact, the
changes are copied to each source account where that information already exists.
If you link contacts with different first or last names, the names on the individual cards won't
change, but only one name appears on the unified card. To choose which name appears when
you view the unified card, tap Edit, tap the linked card with the name you prefer, then tap Use
This Name For Unified Card.
Go to Settings > Mail, Contacts, Calendars, where you can:
Change how contacts are sorted
Display contacts by first or last name
Change how long names are shortened in lists
Set a default account for new contacts
Set your My Info card