Who are tier-1 and tier-2 ad networks? and more

Allow me to apologize for asking such a newbie question. I’m fairly new to the ad world (publisher) and looking to figure out how to go about monitizing my website/business.

I was reviewing the Ad Networks thread stickied to the top of this forum and saw a listing of a bunch of ad networks. The OP stated to stick with tier-1 networks. I am wondering who are the tier-1 networks? Who are tier-2 networks? And if you are trying to monitize a new website/business who are some recommended ad networks to use? I did review casalemedia and tribalfusion whom i guess would rank as tier-1 (based on what i read in another thread) however you must have X amount of traffic before they would accept you as a publisher.

Are there any companies that would pay CPM or anything for that matter for links in an email? For example an email is sent out to a customer and in that email would include an ad (3 lines or so) with a link. Are there any networks that would pay you for that ad/link even if there is no click-through?

Are there any companies that would pay CPM or anything for ads sent out in a SMS text message?

Tier 1s I would say are Casale, VCM and Tribalfusion.

Look into CPA (cost-per-action) networks for email marketing.

And if you are stuck in finding any CPA networks of some quality then look no further, cough

Tier 1 - Tribal Fusion, Casale Media, Burst Media, Valueclick Media
Tier 2 - AdPepper, Remix Media, RealTech Network, CPX Interactive, Canep Media

That is just off the top of my head. There are numerous other networks around, including an increasing number of vertical networks that specialise in a single content genre.

Text links are normally sold on a CPC (Cost Per Click) basis (like most AdSense ads), but are also sold for monthly sponsorships (like Text Link Ads) or more rarely on a CPM (Cost per thousand impressions) basis (some AdSense ads are CPM).

-Tim

So what differentiate between tier-1 and tier-2 ads network? Who decide which networks are tier-1 or tier-2?

In my opinion, the “market” decides which networks are tier 1,2 and 3. The “issues” that are considered include reliability of payment, fill-rate, CPMs, quality of advertisers and ease of use of their member interface. Some networks do well on some of these but, IMHO, only those networks that do well on all can be legitimately called tier 1.