Question about reading facebook messages?

[Rachel L]

I am just wondering if when a person receives an IM message from a facebook friend do they have to open the message in order to know who sent it or can you know who sent it without actually reading it?

[Alison]

They can see who sent it without actually having to open up the message and read it.
When they actually click on the message and read it, then it''ll show you the time they read your message!