No social media
In the royal family, the use of social networks is prohibited. Members are not allowed to have a private account. This rule only applies to the descendants of the queen and their wives. There are a number of reasons that make this rule sound reasonable, but given that this is the age of social media, it could be a little bothering for the more modern royals, such as Kate, not to be able to maintain a social media presence. But regardless of how they feel about this, they are bound to follow these rules.
This rule exists to prevent secret data from becoming public. Crazy as this rule may sound, it actually makes surprisingly sense when you consider how easily messages and images can be taken out of context. There is, however, a way to keep people posted about important announcements from the palace on social media platforms, such as Twitter, Facebook and Instagram, There are official Crown accounts, but these are managed by communications professionals, who are responsible for choosing photos and texts very carefully, which means that if Prince William or Kate wanted to share with the world a photograph of their children, they would have to send it to the communications professionals to post on the official Crown handles.