For anybody who works with web-based content then the “impression” is a very important metric. It used to be the world talked about “hits” but I think we’ve moved on from that: it being the least descriptive and most open to abuse metric upon which we measure successful web content.
So, if you are a publisher of web content impressions are important. Essentially, every page somebody views (and it really should be a somebody and not a web crawler, spider or robot) is counted. The total number of page impressions is one measure of the popularity of your website. Lovely. Such counts help websites understand what’s popular and what’s not and help them refine what they do.
As the boffins who look at all this data got smarter and as web analytics became big business people acknowledged there were other metrics. The number of pages read is not always a good indicator of success. Is it a million pages read by one person or by a million people only reading a single page? Analytics progressed to give us visits and sessions. These “smarter” metrics understood if individual browsers looked at more than one page and over what period of time. If I read 5 pages in the morning, that was 5 impressions and 1 visit. 10 more pages on your site in the evening was another visit and another 10 impressions but, crucially, I was one unique user.
Ooops, I just threw in another metric. Sites needed to get better at understanding all these impressions and visits because, while nice, numbers didn’t tell them much about their audience. So, unique users became important because it told sites how many people come to their site. From that sites can understand how many visits users make and how those visits end up being all those lovely page impressions. It’s like a TV company telling us how many people watched Friends last night. It’s nice to know.
So, why am I talking about all these web analytic terms? Well, that’s for two reasons.
Firstly, any website that sells advertising needs to tell advertisers approximately how many people will see the advertisement. They do not want the scenario that allows one person to have seen all one million of their advertisements. With apologies to my friends in advertising agencies, let’s say that Advertisers tend to like a range of people to see their messages. These measurements are great for helping sites understand audiences.
As a side note, sites generally like these numbers to be as big as possible because it makes them look good. They have a range of tactics to make the number look as big as possible (such as automatically refreshing the page “or part of the page” to make it look like there was another impression). Properly managed websites who sell to big advertisers tend to have their numbers audited by companies like ABCE. ABCE, if you like, helps advertising agencies know that the sites aren’t lying about these impressions, visits and unique users.
Secondly, I am trying to place these terms in context ahead of the next piece I am writing about another important metric to those websites: the ad impression. But that’s for another day.
Whenever you’re working with a site that starts quoting impressions, visits and unique users it’s worth asking how they were collated and are they audited. Are the numbers for the specific site in question or for a “network” or collection of sites owned by the same publisher? Is the publisher using auto-refresh to inflate the numbers and are those numbers both collected and audited by reputable experts in this field? (It is worth noting that auditing can be expensive for small sites but you do need to understand how they have come up with the numbers and you should try to get an understanding of both the number of pages viewed and the number of users that make up those views).
I must caveat this with the notice that I am not a web analytics expert. Such folks will be able to explain the nuances of these measurements in more detail but, think of this as a handy cheat sheet so that you’re not impressed by somebody who talks about their large number of page impressions and then doesn’t put them into context for you.
If you like, I’m performing a public service.
Update: The second part of this mini-series about ad-impressions is now on the site.