Viaplay.se/activate is a URL that can be used to activate a Viaplay account on various devices such as Smart TVs and game consoles. To activate your Viaplay account, visit the URL and follow the instructions provided on the page. You will likely be prompted to enter a code or sign in using your Viaplay credentials. Once you have successfully activated your Viaplay account, you should be able to access the streaming service and all of its content on your desired device.