[zackattack]

>I think people just become friends who get along with each other and don't look for friendship actively

I think this is right. So the question is can you sift out attributes that identify compatible partners? Or is it more biochemical?

[jk8]

Yes, there may be some common attributes and I don't think it is biochemical when it comes to male friends.

I feel that someone can look at the problem differently. To make a site based on a common interest and get people to pay for it. The users of the site will find a way to make friends.

[zackattack]

What makes you qualified to dismiss the possibility of biochemical effects?

[zackattack]

for example, tribal identification via scent, status chemicals