I've got the French version to evaluate, and about this message content, it occured to me the sender is talking about some people who squatted the list of his contacts, probably "unwanted" then would match the meaning.
It often happens on Windows Live or MSN (although one's gotta approve for these contacts to be allowed to get in, but this approval can be made unvoluntarily -if the guy or the girl is a bit dizzy or mixing up with another person-) ( Is that what you mean by "outsiders" )
Another possibility would be that the sender of the message quickly met other people on the internet, exchanged some messages with them for a while, but doesn't want to keep them as her/his contacts anymore.
Does the Russian version precisely tells which kind of "unwanted" contacts it is about
The slang word was used in Russian version. I would use it for the second variant
It sounds to me like the girl deleted all the guys she was not really close/acquainted with. She left only those with whom she still wants to be in contact.
For the English version, I'd use "unwanted", "outsiders" rather being getting in from outside, while "unwanted" says it all : she doesn't want them anymore [as her contacts]!