I tried to find out how "Total time logged in" is calculated.
Here is what I did
I refreshed a page using my account
Then I visited my profile using a device which wasn't logged in. I refreshed the page every minutes. After 18 minutes my status changed to "offline"
Then I refreshed a page again using my account. "The total time logged in" didn't change.
Then I refreshed a page using my account after 3 minutes. "The total time logged in" increased by 3 minutes.
So, the system is working fine for me and I guess it's working fine for almost all of the users.
"Total time logged in" increases as long as the time difference between two consecutive activities of the user is less than x.
This is exactly what I expected. But according to
Bitcointalk Statistics Center, there are some users that have been online more than the time they've been a member of the forum.
Here are the accounts.
hmblm1245btcnfanfroastiekeeweerandomiebcfanmiceyliliamrandomnessiepapperbagI logged in my account on two different devices simultaneously. Refreshed a page by both devices continuously. Both was contributing to "Total time logged in".
In every minute, my "Total time logged in" increased by 2 minutes. So, it seems that those accounts with that long time logged in are using several devices simultaneously. They are always online and never post. What are they doing? Except
hmblm1245 all of them has been created in August 2018.