Who is online
It's difficult to determine who is online using a website. Since there are so many ways that you could build the functionality. However, since I am already sending and receiving at a specific time, I should be able to do one more update to a list or something to toggle if a user is still sending and receiving data. This will allow for the notice of online/offline status.
To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information