Yahoo messenger, yahoo email -any connection in login and log off time?

My friend has two computers, one at home (has installed yahoo messenger), one in the office (do not install any messenger). She has both a yahoo email account and a yahoo messenger account, using the same username.


I always receive yah messenger's pop up message that she logs in and logs off yah messenger within few seconds or minutes. i saw her online for 5 seconds and then offline after 5 sec, sometimes, online for 15 minutes and offline line after 15 min, so i asked her why she didn't call me when she saw my offline messages to her and asked if at that moment she was online. She swore that she never logged in her yah messenger account at that period (the period when i saw her on and offline status pop up message at yah messenger). she said at that period she was at work, her office computer has no yahoo messenger installed, her home computer was closed.


(1)will this situation happen even when someone really does not log in and log off yah messenger but it showed that she did!

Yahoo messenger, yahoo email -any connection in login and log off time?
.l have similiar experiences using hotmail.l find incoming mail has rude things added.This is embarassing as if it can add to incoming mail.Then it can do likewise to outgoing.