My opinion is that there may be a conflict of interest if vendors/advertizers are selected as mods. I wouldn't accuse someone of loading the forums, or deleting "questionable" content posted by their competition at this stage in the game. And until such blatant shenanigans actually happen, I have to believe that such things wouldn't be a problem here (innocent until proven guilty).
But, how does it look to a newb when a they ask a question about which gizmo to buy and a MOD answers... "Buy this one, it's the best" without disclosing that the he is actually selling that particular gizmo? How would that same conversation look if the MOD instead answered, "I sell this gizmo that I think will fit your needs"? Or, what if the mod never said anything, but instead, other posters told the newb that they've tried the gizmo that the mod sells and it worked pretty good? Which of these scenarios feel more appropriate to you? I know which one seems more appropriate to me.
In any event, I'm sure that the SnoWest administration will be keeping a close eye on their mods to make sure they are being fair and even handed. Because if things get heavy handed, I'm pretty confident that people won't stick around long.