It’s true that prior to buying something online, most of us have usually visited a search engine. But was that where we made the decision to purchase?

Online marketers have a habit of attributing a sale to the ‘last click’ a punter made before visiting their websites. But the purchasing journey is far more complex than that as I’m about to illustrate.

For some reason, I always drink Guinness at rugby matches. Prior to match day I may be exposed to a few Guinness ads on TV. Apart from the latest one, Guinness ads are pretty memorable. On match day, I’ll walk past a Guinness billboard (or 48 sheet as my colleagues in offline advertising call them).

I notice fellow rugby fans are wearing Guinness hats as I push past them on the way to the bar.

It’s funny how drinking before midday in a silly hat is socially acceptable but only if the bar looks over a field of grass!

As I hold my tenner in front of me to indicate my desire to be served and that I have the means to make a purchase, I notice the Guinness beer mats strung across the bar.

I scan the draft taps and notice the Guinness sign standing out amongst the vast selection of draft beverages. I order, you guessed it, a pint of Guinness!

Now I’ve got a drink, let me get to my point before its time for another one.

At this point, an online marketer would get out his traffic report and prove that the ‘point of sales advertising’ (or ‘beer mats and towels’ as you and I would call it) generated the most sales!

The fact that I pretty much woke up fancying a Guinness because I subconsciously associate it with rugby (thanks to billions of pounds worth of sponsorship) had nothing to do with it!

In case you hadn’t spotted it, the bar is the search engine in this increasingly tenuous analogy.

I didn’t just walk up to it, give the barmaid the keywords ‘cold’, ‘beer’ and ‘alcohol’ and make my selection from a list ordered by relevance.

When considering where we are getting the best from all of our online activity, we must consider the bigger picture.

Banner advertising has suffered from having its success measured with a ‘last click’ mentality.

A typical punter can be exposed to banner ads many times on different websites before finally clicking on one. They may never do so, but might remember some of your brand messages next time they see your name in their search results.

We need to analyse the full engagement history of customers across all online activity to find out what is working best. It is often hard to find the right technology to correlate this data as media owners all have their own diverse reporting systems.

But if you managed to pull it off, you will find that paid search advertising in isolation is not always the best marketing investment.

* Chris is head of digital at WAA ( E-mail