why should we do that?

You do not have to do exactly as what it described in the article. However, you can learn something from those statements in the article and apply theories to adjust in your own life style.

first, thank U ,your artical seams useful ,but sorry i don't think so ,may be different people have different thought. by the way i'm curious about that u have lots  of money but your experience scores are below zero ,why? please.

This is just a forwarded article. I think it is a good source for non-native English speakers, especially starters to improve English reading skills and learn something from each lesson. It seems that you do not have language barrier, so this article cannot help you much.

In addition I was wondering the same thing as you wondered about my negative experience points. It just happened last night.

A few days ago, one of my threads was rated as hot and great (加精华) by two forum admins. The system mistakenly rewarded me twice with both 500 experience points and 500 forum currencies. However an admin corrected the system error and deducted the repeated rewards from my account.  My total experience points were under 300 before the admin deducted my points. Therefore, my experience was negative after deduction. By the time you read my thread, I haven't earned any points today. Yet, I have earned some points by posting comments and collecting "Everyday Rewards (每日红包)" this morning, so my current total experience points are positive now.

Finally, I want to tell you that you can earn many points from posting valuable, educational, and original threads, because forum admins would cherish your work and great contribution to the forum.   

thanks a lot. of course, you did a good job just in 9 hours (your on-line time）how could you be so nubility