A snapchat thing that a lot of young people do. Basically, every day that picture messages are sent to, and received from a user, their daily streak builds up.

Basically, people send random pictures (selfies, sometimes just black), and caption it streaks. If you reply with another picture message, your daily streak goes up. For some people, this is a very important factor of their lives. For normal people, it doesn't matter.

Here’s a less emotional explanation:

A streak just means daily communication on Snapchat. Like if we had a counter here that said “you’ve made a post every day for the past 18 days on poal” except it’s for a specific person on Snapchat (which is just a messaging app)

It has 2 purposes. One is to keep people using the app every day. The other I’d for the app’s users - like any social connection irl, you have to reach out regularly to the other person or you will drift apart. Streaks encourage that behavior, and also help you identify those who see you as a priority. I consider it a pro-social feature and you can absolutely use it to strengthen relationships you have with people who you actually see in person. Depending on your age it’s expected and fairly mundane, just like communicating via email or slack is expected for most work environments.