Appear offline, why?

1) Awkward, seeing your friend there and not doing anything is just weird to me, if you ain't engaging, you are ignoring so better not ignore, just lay low.
2) Utilize the fuction provided by MSN and that is to message people when they are offline. Use it!
3) Allow people to get use to see-ing me offline so when they see me/or anyone offline in their list. They still feel that can are connected thru chat message they can still send.
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(non-exhaustive)