Snapchat is set to overtake Facebook as the social media channel choice for 18-24 year olds in the UK this year. By 2019, Snapchat is forecast to have 5 million regular users 18-24 vs 4.5 million for Facebook. This is according to a new report by eMarketer and it will put Snapchat ahead of Facebook for the first time in the UK. Snapchat is expected to grow 18-24 year old users in the UK by 350,000 users while Facebook is forecast to have a second year of declining use. The 4.