This thread is not about who you are cheering for, or who you think is going to win.
Simply put, what would be the best possible outcome of this fight, from a strictly business/ marketing sense? What would set up better matches and best selling PPVs?
If Anderson wins
Even though he already lost twice to Weidman, there could be plenty of interest for a 3rd match down the road, if Anderson beats Diaz by KO. Two legit wins for Weidman in spite of the clowning and the leg break, but a third fight would be sellable nonetheless. If AS wins by close decision, maybe we could see AS vs Machida, if they are willing to fight each other. (A few years I seem to remember that they wouldn't, but this may have changed)
If Diaz wins
We see a lot of talk about a rematch between Diaz and Lawler on the forums, but I think that Nick would need a WW top contender first. Their first fight was a long time ago, and Nick hasn't won a fight at WW for over 3 years. WW still has plenty to offer, but with guys like Rory and Lombard waiting in line until the Lawler Hendricks saga is over, having Diaz get a title shot from a win in a differrent weightclass may not be the best move by the UFC. However, a win over Anderson Silva opens up possibilities for Diaz at 185. There would be plenty of great money making fights for him there.
All this to say that there is benefits regardless of who wins, but I think that AS winning would probably generate more interest down the road. Nick will always be marketable no matter what, but AS regaining some of his pre-Weidman aura would be great for the UFC, especially with GSP gone.