Skype, the telephone of the 21st century
Though the app was initially free for the first year, after which a small subscription fee of $0.99 was charged, it was decided to make the app completely free in early 2016. This came shortly after Facebook bought the app. The company intended to profit through commercial ventures, keeping it free for users.
In the broad sense that this app allows you to communicate with others socially, it could be considered social media. However, in a more narrowly defined sense, the app is an instant messaging app. The scope of what this app does is much more limited than typical social media services and apps.
The platform encrypts messages end to end with unique lock and key information. This means that the information being sent between the participants in a messaging conversation are the only ones who can read said information. Even the company who own the app can access this information, making it completely secure for users of the app.
Though the app is encrypted end to end, it is still possible to be sent harmful or offensive content over the platform. It is important to make informed decisions regarding who you communicate with on the platform, what you share, and what you accept from them while using it.
There is no native application for desktop platforms such as PC. There is, however, a web client which can be used in tandem with your phone. The web client is verified by the app on your phone, allowing you to message from your PC like you would in the regular app.
The app is a secure and private messaging service that works by setting a unique encryption key for each conversation. Information is then encrypted end to end, making it completely private. The app is tied to a phone number and uses data, rather than SMS, to send information between contacts.
When a person is blocked in the app, they are not explicitly notified. There are, however, indicators that may let them know, such as not being able to see when the contact who blocked them was last online. Blocked contacts also cannot see your profile photo, or make calls to you.
The app is intended to be tied to a mobile phone number, and can only be set up on a device after a confirmation SMS message with an activation message has been sent and received. However, there are ways to get around this limitation using additional apps and techniques during setup.
Once the app is set up on a device, there is no login process. For the web client, a QR code will be displayed when you go to the client. In the app, pull up the menu and click "WhatsApp Web". Click add a device and point the camera at the QR code.
Sending a photo over WhatsApp can be done one of two ways. Either click the paperclip icon and select an image from your device, or click the camera icon and take a new photo. There are options to edit the image, such as resizing, or drawing on it.