In order to see advanced reports, you have to register.
Registration is simple and only takes one minute.
You will be able to see full activity of your tracked IDs. This means you will know exactly the time one ID logged in, how long it was connected in a session or how long it was connected entire day.
You can track activity for several days. There are reports that give you an overview of time spent online on Yahoo! Messenger for each tracked ID. Thus, you can see a brief list with every day and actual time spent online.