I thought I read somewhere that the "???" trust score basically means the system is unable to help you determine a score so it is up to you to decide whether the user is trustworthy or not. On my end Muhammed Zakir's trusted ratings are all positive and he has a trust score of 9 currently, so I guess it also depends on who you have on your own trust list as it affects other people's trust scores. Feel free to correct me if I'm wrong though.