Hello Magma!
Thanks for making a suggestion! We really appreciate players giving feedback and suggestions on Potterworld, as it helps the server grow and improve.
After discussing your idea with the other Poltergeists, we have decided to decline your suggestion, as there are some privacy concerns about this. Some players might not want other players to know when they were last online, so we need to respect that. However, we have taken this idea into account and might consider something similar in the future!
Have a great day!