First off, I'd like to wish everyone a happy new year. After I finish writing this I plan on opening a bottle and leaving lots of drunken comments on all your blogs. <3 I've been busy a bunch lately with all the holidays and getting everything taken care of for college. New term starts on Monday, so after that I will be back to my regular posting and stuff. Anyways, on to the point of the post.
This time I'm going talk advertising on your blog. Specifically, the different types of ads, different ad companies I've used, and what type of ads are best for the type of traffic your blog gets.
CPM
CPM ads are ads that pay just to be shown on your pages. They'll have a set price that's on a per thousand impression basis. A CPM ad with a CPR of $5.00 will earn you 5 dollars after 1,000 impressions, gaining fractions of that amount for each one. Whether or not they're clicked on makes no difference on the amount you earn, all the matters is you have enough traffic to make CPM ads worthwhile. They can be anywhere from 50 cents to 10 dollars CPR but the average starting one is about 2 dollars.
CPC
CPC ads are ads they pay every time someone clicks them and are probably the most common type. Most advertising companies that don't have minimum requirements run CPC ads, Google and Adbrite are some exceptions. They're entirely based on how many people click the ad and can pay anywhere from a few cents to 5 dollars per click, averaging about $1.50.
CPA
CPA ads are ads that only pay out if they get the desired result. There are ads that only pay if the target buys something or if they sign up for an account ect. You might have seen Net-flicks advertisements that say "sign up using this special code to receive a discount!" but it's actually a reference code so they pay the right person for the referral. This is usually a bad option for webpages because it puts all the pressure on you to sell whatever it is. Unless you're an internet star and can influence people, it's better to stay away from these. CPA ads can pay a certain percentage of the sale or a flat rate of $25+ dollars.
What advertising types are best for my website?
Choosing the right type of ads can be difficult. Usually, companies are dedicated to a specific type of advertising so you have to sign up with the ones offering the type you want. (There are a few exceptions such as Google Adsense and Adbrite)
If most of your traffic consists of first time visitors or gets most it's views from search engines, than CPC is probably a good choice. Visitors from search engines usually read the page they entered from and than leave and don't generate enough impressions for CPM ads.
If your site's traffic is mostly return viewers than CPM advertising is probably best. People tend to only click an ad one time, even if the content interests them. If you clicked an ad you were interested in, why would you click it again the next time you saw it? CPM lets you get the most out of return viewers because even if they don't care about it, you can show them the same ad over and over and still make something. Another reason is, even if the same person did click the ad again and again, CPM advertisements will disable earnings that come from the same IP address if they catch it repeating. Blogger users usually fall into this trap because they have repeat readers by nature. If you've been having earnings cut OR have been banned from Adsense through no fault of your own, this is usually why.
Your setup has effect on what ads you'll want as well. Does your site have lots of pages that require your readers to navigate a bit to read what they want? Then CPM is good for you because you'll get lots of impressions but also because readers tend not to stay on the page long enough to see a CPC ad if they're clicking through to get to what they need.
On the other hand, if your site has few pages with lots to read or if all your content is on your home page, then CPM works well. If your readers stay on one page for a few minutes then they'll notice the ads.
So, part 4 will be cover some of the basic advertising companies. It was going to be part of part 3 but I've had like 4 shots since I started typing and I am in no condition to be offering advice.
Happy new years! :D