Okay so lets so we have a user that wants to scam you, lets call this user Time To Buy.
Time To Buy is going to contact you pretending to be Duhfault, and go through the process of talking to you.
Time To Buy is then going to contact Duhfault pretending to be you, trying to get somewhat of the same conversation that you and him had.
Time To Buy is then (pretending to be you) ask Duhfault to send him a pm on sythe forums (from which he will link your account)
The real Duhfault then sends you a pm, not actually having talked to you.
Then Time To Buy (pretending to be Duhfault) is going to scam you, while you are under the assumption that you are talking to the actual Duhfault.
Its called a "man in the middle" scam and is becoming very popular nowadays. Check this:
http://www.sythe.org/report-scammer/1331084-attention-all-skype-proofs-must-include.html