The answer depends on your needs and your site. What works for one website won’t necessarily work for another. However, there are some broad guidelines that are pretty reasonable for most sites. So this discussion will make the following assumptions:
1. You want to maximize profits
2. You have the time, knowledge and connections to execute these steps
3. You’re willing to sacrifice some User Experience to earn more
If you have less than 1,000,000 monthly pageviews
Keep it simple and focus on growing your traffic!
Setup AdSense and consider working with one of the content recommendation widget companies. If your website frequently mentions products, setup an Amazon Associates account, or install a script such as Viglink. These 3rd party affiliate networks help you quickly reach beyond just Amazon, but they also take a cut of the profits.
If you have more than 1,000,000 monthly pageviews
Start working your stack towards the one below. You don’t have to do this overnight! You want to mix different types of advertisements without going overboard on any one thing. Like a stock index fund, this is a defensive play intended to give strong, but consistent performance over the long-haul. If one of your networks tanks, you’re still covering your bases.
- Direct Deals
- Header Bidding
- Banner/Display – dynamic allocation, PMPs
- Banner/Display – 100% fill networks
- Banner/Display – remnant network
- Banner/Display – backfill
Note that I’m not advocating you have 11 ads on every page! The first 6 items in this list are the same thing, banner ads, with different priority levels. The other units need to be considered in the context of your audience.
How many partners do you need?
For Direct Deals
For direct deals, you want as many as possible! As long as you can deliver the impressions, direct deals will command the highest CPM. Just make sure it’s worthwhile. A small deal requiring a complex execution may not be worth the trouble.
For header bidding, the jury is still out on the right number of bidders. In simplistic terms, the more bidders, the better. However, practically speaking it will take some time to arrange and implement these deals. In addition, latency becomes a concern as you add more bidders. Two bidders seems like a great place to start. Then you can experiment with adding more.
For dynamic allocation, all you need is AdExchange. Technically, AdSense can also operate in dynamic allocation mode, but AdExchange has better controls, better reporting, and allows you to setup Preferred Deals (PMPs).
100% Fill 3rd Party Networks
Take as many as you can manage. You will need to keep a close eye on performance, since high discrepancy could ruin the deal.
Remnant 3rd Party Network
For remnant networks, One is enough. There’s little evidence that running a long passback chain is any more effective than running a single network. Use a single-hop to send any unfilled impression to backfill.
You need 100% fill but the CPM can be variable. This is a catchall for impressions that nobody wants to buy. Expect extremely low CPMs here with a high percentage of mobile and international traffic. Instead of running backfill, this is a great place to run house ads instead.
If you have original video, pre-roll is very valuable. Run AdX Video and one premium video network.
If you’re doing in-feed video, one network is enough.
For native in-feed ads, one network is enough.
For widgets, one network is enough.
Affiliate sales are a whole separate topic. If you can work them into your stack, do it!
Mobile-only ads are great. One network is enough.