In this case 'tribe' just means a group of peers he can relate to well and feel like part of a group with. That might be an established LW group or it might be something else.
I don't know anyone in Pheonix, but try searching the discussion board for 'pheonix' and/or making a new post about it.
Edit: There's a meetup group! Arrange to meet them!
I may look into that. I was directing that bit at Andrew, as we have skyped and I thought he was around that neck of the woods. Far-ish, but closer than MN, that is :)
(Andrew is a pseudonym because he is a little worried about showing up in an internet search; please respect that and do not use his real name when posting below).
Andrew is an established and valuable member (link to highest voted post) of the LessWrong community. Sadly, he is without a tribe; he lives in a relatively small city where he has not found a tribe to belong to despite considerable effort. Being part of a tribe would improve Andrew's life considerably. Andrew is not attached to the area and quite willing to leave, doesn't know how to taskify getting himself a tribe.
Big decisions like moving are often easier and better executed when made with outside input. Therefore, I am putting together a Special Relocation Task Force to aid his efforts.
Besides helping Andrew, I am also interested in answering the question 'will rationalists be good at this?'. They should be; rationalists should win. If they are not, something is wrong and I want to know about it. This experiment seems like a good way of answering that question.
Here are some basic facts about Andrew: