The art and science of online advertising continues to evolve and CPRT might be a helpful way for you to think about your online advertising campaigns. Whether you are a blogger seeking readers, a businessperson hoping to sell goods or services, or an advocate promoting a candidate or cause, you are trying to get people to hear your message and respond. One way to do that is to place online advertisements.

In the early days, online advertising was a lot like other types of advertising. You placed your ad, your billboard, or ran your spot in a place where you thought it was most likely to be heard. Yet with online advertising, there was a whole new component. You could measure things much more precisely. So, instead of buying a particular place for your advertisement, you could buy advertisements based on the number of times it was actually seen. This sort of advertising is often referred to as CPM advertising, or cost per thousand impressions.

Yet getting someone to see your advertisement is only the first part of your task. What you really want is for people to respond. So, companies started selling CPC, or cost per click advertising. Yet even clicks are but the most rudimentary type of response. What you really want is for people to buy your product or spread your message.

Now, everyone is talking about various forms of CPA, or cost per action advertising. One action is buying the product. Another is signing up on the site. This is CPL or cost per lead advertising.

Another evolution is getting highly sophisticated in targeting advertisements. A company selling online advertising can find ways to get demographics of visitors and set up the advertisements to meet the specific needs of an advertising campaign.

Yet most of this seems to miss what I think is the most important with the Internet. The key change that the Internet has brought is the movement from broadcast oriented communications to network or community oriented communications.

Some advertisers see things go viral online and wonder what it would take for their advertisements to go viral. So, what does it take for something to go viral? Not to oversimplify things, but put simply, you need to get people to repeat your message to others that will in turn repeat your message in their communities, and so on.

This gets to CPRT advertising. Twitter is currently the hot area to spread a message. This is done by ‘ReTweeting’ the message. So when you look at your advertising campaigns, are you advertising on a network that people are more likely to retweet your message? If you’re targeting viewers, are you managing to target those most likely to spread your message? What is your cost per retweet, CPRT? Are you managing to move your advertising from a broadcast to a conversation?

(Cross-posted at DigiDay:Daily.)