PLEASE READ ALL THE INSTRUCTIONS! DISCLAIMER: No, this does not use the Scratch API to detect whether a user is online or not, so for example, it can't detect whether Griffpatch is online or anything like that. The user has to have a tab open with the project running in order to do this. Click the flag and you can tell if I'm online or offline! This will only work if I have the tab open though. :P You will have to remix to test for others because clicking see inside disables cloud variables. But be warned; it only works if they have your remix running. So basically, the user that you test for has to be running your remix in a tab.
C2A (remake cuz this project is cool)