I know that one publisher may have multiple traffic sources bidding for placements. But can multiple traffic sources bid for the exact same placement on a site? Or are individual zones owned by only one traffic source?
One traffic source may bid for the same if they are connected to the same ad exchange, as far as I know.
So theoretically, the same advertiser on different sources can be bidding against themselves, but you almost never have someone who creates a lower profit for themselves by doing that since they optimize individually - meaning one of their bids will stop if it's not profitable, and continue if it is only. Either way, your overall profit should increase.
This is just a very theoretical scenario though, you aren't driving prices up for yourself. The market is too big.
Thanks for your reply. That makes sense, one thought I have is that the market might not be that big if you are in a small geo though.
Even then though, if it's you against yourself, the increase in price and effect on your results should be minimal since you are likely running the same thing twice in that market, so you only pay as much as it's profitable for you.
Of course, it's hard to say exactly what the effect is but it's just so small that it's not something worth pursuing more, since there are easier avenues for improvement.