In order for your contacts to benefit you, you must take some care in setting up each contact. SMS/MMS will not work the way you want them to, email clients may seem to be vacant and contacts may not sync with Facebook if you don't follow a few simple rules.
- SMS/MMS: For any SMS/MMS app (stock included), your contact MUST have a MOBILE phone entry. A quick setup of a contact, an import from another device, or a dump from GMAIL may not have set this up properly. If you are unable to send an SMS/MMS message out through the app (type in name, name comes up), you DON'T have a mobile phone entry for that individual.
- EMAIL: Contacts MUST have an email address for email clients to work. This may seem obvious but it can occasionally be overlooked. If you don't have one, you can't search the contact.
- FACEBOOK: In order for Facebook to automatically match up to your contacts, they must have identical names. I have a few friends that decided not to use their real names on Facebook, which gave me two entries. To solve this, find one of the entries, edit it and then hit the menu key. Select JOIN and then you can merge that contact with the other, creating one contact.