shouldn't this fall to unsolicited PMs and can get the user who sent it banned from the forum?
The scammer has been banned. Sharing phishing links is a bannable offense if it's reported to the moderators.
Just curious to know how does this scam is being done and how does it impersonate another User ?
Does it take you to outside forum ?
It's not impersonating another user. The link shared is meant to trick you into signing in thereby stealing your information which the scammer later users to hack your account
Yes, @Beparanf explain this very clearly and it is really tricky as anyone can fall for this scam if he did not know about it.
I will now double check the URL before entering any credentials every time on bitcointalk or any other forum.