I agree, people are really looking into the keylogger theory, but actually I think the goal of the scammer is to have a "legitimate" (residential) internet conn

I agree, people are really looking into the keylogger theory, but actually I think the goal of the scammer is to have a "legitimate" (residential) internet connection with which to register hundreds of online accounts, or purchase ads, etc. If the IP gets blacklisted by a service (like Facebook), no problem, the account holder will probably notice that they can't get to Facebook anymore, call up the ISP and get a brand new IP address. All this for just $15/month.