A little Pandora's box you opened with your comment below, @jaynie, and points well made on both sides. So, before I get to your question, I'll just repeat what I've said elsewhere: just downvoting without qualification is not helpful particularly given how it's been (ab)used on this platform in the past. As a consequencd of this, the behaviour is often taken personally. My sense is that changing this will take a long time and possibly never will. Consequently, and who knows, this may yet feature in HF..whatever... in the future.
Now, as to your question about tribes: I've "joined" a couple and to be frank, am not sure of the point. Perhaps it's my resistance to being part of a herd or the fact that I completely miss the point with smart tokens/tokenisation. Or perhaps I've just not read all the blurb....
So, unless I can be persuaded that there is material benefit to joining a tribe and/or selecting one platform over another (like @SteemPeak and/or @steempress) for posting and/or participating, I'm not sure I see the point.
That said, I do like the idea of communities like PHC and there's a part of me asking whether there's a difference between a tribe and a community - except the absence of token? Or are they exclusive? Seems to me, not, and that one can be a member of a few.
My 2c worth on the matter. I will be interested in what you find out and how you might decide to move forward.