There are no official backup sites for bitcointalk.org.
I think that most of these sites copy bitcointalk.org's content so that they can confuse Google into showing their results high-up sometimes, and then they either have ads to make money off of this, or they operate as phishing sites. I don't know. Don't enter your password into any other site.
Thank you for your reply.
Cannot they be taken down by DMCA because an average person may try inputting their login ids there instead of the main site. Specially when they are accessing from their mobile phones it will camouflage with the actual site and in a hurry he or she might input their login ids.