I'm not sure how much actual affect this will have on loot.
While
MA advertises over 300,000 participants most of those are inactive and/or 2nd avatars.
I think advertising companies generally pay for 'impressions' or views of an ad. So,
MA will need to give the advertising company some actual figures as to how many people were logged into X server to see Y advertisment.
Since I think the active player base is actually pretty small (less than 10K) I'm not sure how much revenue will be paid to
MA as compensation for the ads. In the end, I think any affect will be small.
That being said, I'm sure
MA will turn up the loot after ads start appearing to make sure everyone is excited about the concept and to help pull new noobs to the game.