There is more than one method to let people know that you have joined snapchat. And one of the ways is to cross promote you snapchat account through other social media platforms. You could also make use of the URL and spread it around. If you wish to build an app like snapchat then you need to focus on ways through which user profiles can be shared around with other users. You can even integrate a features of codes that can be scanned to efficiently find users and connect with them. What are the other methods that can be added to apps like snapchat to help users connect with one another?