I've tried as an advertiser, almost every PPC company I've seen, including really #*$!ty ones. And now, when I feel like I've seen this market, I really don't understand why would a publisher use any other network then tier 1 networks. It is clear that Miva, Enhance, 7search and many others are paying less then Google pays adsense publishers or Yahoo pays YPN publishers. So why on earth does anyone want to be a Miva publisher? The only reason I can think of is that if your site does not meet the standards of Google or Yahoo, you will have to look for something else. Is there anybody here who is a publisher of a tier 2 network that can explain why it is a good idea to work with these networks?
I can think of several attractive reasons, tier2's can be and are better earners if you have an attractive revenueshare deal and have traffic in the right niche market.
Another advantage is that you can often agree a contract duration be it 6mths or 2 years. As long as you maintain your traffic and the bids don't tank that is fair security.
Obviously you need to be confident that the tier2 is going to still be around and is in good standing two years down the road. In that sense Google perhaps seems more of a sure thing, its not going to go bust anytime soon. Then look at how they can play around with the percentage share publishers get from the clicks and how it can go from great to almost nothing.
I think with the right deal, tier2 engines can be very lucrative and very stable income.