Sounds like a really stupid question, and have been doing this for a few weeks without really thinking about it.
To keep it simple, for example on PopAds if I bid $5 CPM and see myself at position 10. Does that mean the person will see 9 pops before he sees my offer?
There's 100 websites. Based on the algorithm, the 1st bidder will probably get something like 70% of the traffic on first session depth. That's 70 sites.
2nd bidder, another 15%. That's 15 sites.
So you'd get something like 1 or 2 sites or 1st session depth. Just a rough example.
What if it's per placement? (eg position 1 vs 5 on placement xyz)
Its hard to say how a particular network distributes their traffic, as the algo changes a bit from network to network.
As a site owner, when selling pops to a traffic network, you usually get the option to set the frequency of showing the popup/popunder to the same visitor. So in this case, the first impression should be sold to the highest bidder, the second impression to the next one etc. In real world, it rarely works like this, as the networks dont want to send all traffic to the same landing page and the same buyer. So they set the algo to distribute the traffic more evenly.
I have seen algos do all kinds of distribution - all traffic to the highest bidder, all first impressions to the highest bidder, mixing the impression to achieve more or less consistent traffic quality for all, certain % distribution ... generally speaking tho, in almost all cases, bidding higher gives you better quality traffic.
If you can figure out what the algorithm actually does to distribute traffic based on bidding position. that information can be quite powerful in developing your bidding strategies.
For example, knowing that a specific traffic source tends to give 30% of traffic to position 2 whereas another one gives 10% of traffic in the same space can really inform whether you bid on larger spots at lower places or try for exclusive position 1 on smaller spots.
And there are lots more sneaky tactics you can get into too. See my article on competitive bidding (linked in my signature) for a couple of examples of those.
Where can you see your bid position on popads?
On another note, I realized that if I setup multiple campaigns on Popads at different bid prices and run them all at once, the highest bid runs first and then after that budget is depleted it goes on to the second highest bidding campaign.
In summary after setting up campaign