The Contact Share app has a simple panorama with two pages: contacts (for sending contacts) and received (list of contacts sent via SMS/MMS).
Sharing a contact is a three stage process. First you choose which contact you wish to share from a list of contacts drawn from the People Hub. Secondly, you choose what information you to include in the shared contact card. By default the app will include name and default number in the vCard, but you can also opt to include other information (on a field by field basis). And third, you choose whether to send the shared contact via email or SMS.
With Contact Share installed on a Windows Phone device contacts (vCards) can be received via email, or via SMS/MMS. Many mobile phones support sending vCards in this way; the functionality is usually an option in the address book application (e.g. in Symbian Belle a long press on a name in the Contacts app brings up a pop up menu with a "send as contact card" option).
If a vCard is received by SMS or MMS, it is listed in the received page of the Contact Share app (and is filtered out of the Messaging hub). Tapping on a received contact opens up an "add new contact" screen, from where you can select which information to use, and add the contact to the People Hub.
If a vCard is received by email, it can be opened directly from the email by tapping on the appropriate attachment, which opens up the same "add new contact" screen described above. It's a shame that the app can't list vCards from both SMS and email in one place, but that's due to limitations in the Windows Phone's APIs, rather than the way the app has been programmed.
Contact Share, much like Contacts Transfer and Network Setup, does a great job of filling in one of the areas that really should have been built into Windows Phone in the first place (a reflection of the platform's relative immaturity and an intial Western world focus)
Marketplace description:
Contacts Share is a quick and easy way of sharing useful contact details via SMS or email. You can seamlessly share contacts from almost any phone – Symbian, Android, iOS, BlackBerry and others as this useful app uses standard Vcard format. Once shared, you receive them either in the app’s own inbox if sent via sms. Or if emailed, you’ll find them in your email inbox. And your new contacts appear in the Windows Phone People Hub, from where it’s easy to call, mail, chat or follow friends on your favorite social network.
Contact Share, which is exclusive to Nokia's Lumia devices, can be downloaded from the Nokia collection in the Windows Phone Marketplace. You can also download the app by scanning the QR code on this page.
Contact Share was previously only available in select markets (e.g. China). Our app tracking indicates that Camera Extras is now available in the following markets: AR, AT, AU, BG, BH, CH, CL, CN, CO, CR, DE, ES, FI, FR, GB, HK, HU, ID, IE, IL, IN, IQ, IS, IT, KZ, MY, NL, NO, NZ, PE, PH, PL, PT, QA, RO, RU, SE, SG, SI, SK, TH, TR, TW, UA, US, VE, VN, and ZA. The remaining markets are expected to follow in the next few hours.
It's important to note that in order for Contact Share to function correctly your phone must be running the Windows Phone 7.5 Refresh ("Tango"). The Nokia Lumia 900 (global variant) and Nokia Lumia 610 shipped with this version. The "Tango" (8773) update is now widely, but not universally available, for the Nokia Lumia 800 and Nokia Lumia 710.