What is an "Impression?"

I've been using some PPC ads for a little while now (haven't earned squat, though), and I've gotten very familiar with the terms, "Unique Visitors" and "Page Views," but what are "Impressions?"

 

An impression is the number of times a particular ad unit is displayed to visitors. Most contextual advertising services (AdSense, YPN etc) amalgamate the impressions on a page, so the value given is the same as the number of page views.

 

How many times an ad is shown, usually measured in thousands.

 

^ sometimes you'll see ad programmes referred to as cpm,
It means mean then pay by 1000 impressions. m is the roman numeral for thousand.

 

I think we get 3 or 4 impression point for one visitor , correct me if i am wrong .

 

I think it depends on the service provider. Like I said they usually count all the impressions on a page as coming from a single ad unit.

 

Source

 

A single ad unit appearing to an Unique visitor = 1 impression.

 

This all very confusing

 

Thanks, guys. That really helped. CPM sounds like a pretty good thing, maybe easier than PPC. What do you think? Are there any drawbacks? I'm sure it pays very low, but when you get hundreds of visitors a day and you have a lot of ads, they might not click them, but they're always displayed.

 

If you've got thousands of visitors every day I would keep to PPC to be honest. A typical CPM would be maybe $1-2, whereas if 5% of your visitors (50 out of 1000) were to click on your ads you'd probably do better than that with something like AdBrite depending on your niche and source of traffic.

 

Thanks, CountryBoy. What if I get around 400-600 visitors a day? So far, at 4:38 PM, I've gotten 575 uniques, which is more than usual, but the past week I've gotten 700 and even 900 one day, but still almost no clicks. I think the most I've ever gotten was 8 clicks last month. Do you think I should try a CPM? What is the best CPM?