I've always wondered this. The Durden family. 

How did they come about?

Whats the relevance to fight club in their portraits?

Why do the boss, lhm and rhm keep their name whilst the rest don't?

Just curious, that's all. 

A long while back we all gave idea's to a NPC family that would spawn every few days. Fight Club won. So the top three stay the same while the rest are randomized.

The site needed a way to feed more kills into the game after AJAX wack was implemented and created an "everyone and their mother is trying to shoot, but no one has anything to hit" problem. Thus MIAs and Durdens were invented as a fun way to re-balance things.

The top three stay the same so that there's an easy way to distinguish the NPM crew. TylerDurden/Marla/Robert and their pictures were picked by a contest.

Thanks. I always wondered what the history / background on them / the feature was. Cheers for the info. 

cheers for the info buddy!