The famous application WhatsApp also landed on some Nokia Series 40 device in version 2.0.6.
The application, for those not familiar, allows you to communicate for free with friends via text messaging device with Symbian, Android, iOS and BlackBerry by using a data connection.
You can download the application by accessing the website http://www.whatsapp.com/s40/directly from your device!
Alternatively you can free download the installer from this page of Ovi Store. At the time compatibility is guaranteed only on models Nokia C3-00 and Nokia X2-01.