Gmail chat hacked?

Do you have a question? Post it now! No Registration Necessary.  Now with pictures!

My friend told me that he thinks his gmail chat was somehow
compromised by someone he knows. That person, apparently feeling very
smug and untouchable, told my friend that he did it using some sort of
program that he downloaded, which involves somehow using sockets to
listen in on the specified gmail user's chats that are in progress.
All you have to know is the user's gmail address. Also, it seems like
the chats that are off the record cannot be retrieved by this program.
I am a program, but I don't know anything about network or socket

Does anyone know if it is actually possible to do something like this?
Is it as easy as downloading a program off the web? Is there any way
to protect yourself from this?

Thanks in advance.

Site Timeline