Using the Meebo Chat Window Widget
I've discovered that even though I may be logged out of my IM people still have the opportunity to leave me a message via the chat window. The next time I log back in to my IM I get the waiting message. The problem with this is that unless the person leaving the message also supplies their contact information I have no way of knowing who that person was because I only see "MeeboGuest" on my end.
There are a couple of things you can do to avoid this if you are using the chat window widget for your IM service. You can add write some text to go along with your widget to indicate to patrons to leave their email or IM address when leaving a message offline. Also, you can have your IT staff write code so that your widget only appears on your website during the hours it is staffed. This may also help alleviate confusion for patrons of whether someone is actually available to answer their question in real-time.