The idea is the same as del.icio.us - only for people, you tag yourself, you tag others, they tag their friends and so on. So when you are looking for something, you think of tag that broadly matches the subject, then you find the person closest to you and available that can help you with this subject, maybe just give you a few pointers or narrow down your search. It works already, and it will work for the story that you posted about computer optimization. Why do you trust CNET? If somebody pays high enough they will post anything….

At any point in time some of my friends will have interests that are diverging from mine and will therefore not be able to help me with this.

And if all my friends were on the same page we would get a giant echo chamber that would never bring anything new in the mix…