Do PPC tracking parameters affect Search Engine Spiders?

PPC ads require tracking parameters like '?source=google'. Since search engine spiders are known to have problems traversing links with many parameters, this article explores the consequences of such parameters, and proves they don't affect search engines.

Tracking PPC campaigns requires the use of either specific landing pages or a 'tracking parameter'. Let's say you're advertising in Google and buying the keyword 'Rhubarb'. When the user types this as a search query, the URL where they see results will look something like this :

http://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8&q=rhubarb

Let's assume Bob is both optimizing his site for this keyword, and buying the keyword. From the above page the user could click through to www.bobsfruitsite.com from either the traditional search listing or the PPC ad. Thus the clickstream in each case would be :

Traditional

http://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8&q=rhubarb

--> www.bobsfruitsite.com/

PPC

http://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8&q=rhubarb

--> www.bobsfruitsite.com/

Of course they're the same URL for the clickthrough. Web marketers are conditioned to look at the referrer for interesting data, and indeed in these cases we would find at least the keyword, but notice there is nothing in the referrer that distinguishes paid from free search listings.

Referrer doesn't help distinguish

The referrer is quite simply the page the user was at before clicking into the current page. Since this is the same for both PPC and free search ( ie, they're on the same page ), you get the same referrer.

Use of tracking parameters

The lack of useful referrer information has lead to the widespread use of what are popularly termed tracking parameters. Parameters are name / value pairs, appearing to the right of the ? sign. Tracking parameters are added to a URL purely for the purpose of identifying something about the incoming link, often the source of a marketing campaign.

Using the above example, we could change the PPC clickthrough URL to look like this :

--> www.bobsfruitsite.com/?source=google

Within the AdWords UI we can simply specify any URL we wish for each ad. The same is not true of course for the URLs the Google search engine itself chooses to direct visitors to within the free listings.

In this case the 'source=google' is a tracking parameter. When the user clicks the ad the entire URL will be sent to the web server, and it will be logged complete with all parameters

Tracking parameters get logged, but do nothing else

When the server reads the request for the home page + parameters 'source=google' it will execute any server side scripts. The source parameter is presumably not being used by any ASP / PHP / JSP code within the page and so is ignored (if you suspect the tracking parameter names might already be used for other purposes within the site, choose other names)

We now have a way to distinguish paid from free search. Anything with a landing page that contains the parameter 'source=google' must have come from a paid listing

Adding more info to tracking parameters

There's all kinds of useful stuff a marketer can throw into the tracking params, for example :

--> www.bobsfruitsite.com/?source=google&campaign=5&group=2&creative=3

Tracking parameters and search engine spiders

'But wait' came a cry from the audience. Everyone knows you can't add all those dynamic parameters to a URL and expect the search engine to be able to crawl the site. There's all kinds of articles on the net about how you need to limit the use of parameters that appear inside URLs.

If the search engine crawler were ever to crawl those parameters, we might have a problem. However, those parameters only ever appear in PPC ads. Although the ads appear inside a search results page, they are only present because the advertiser chose to list against the keywords. The traditional search results appear on the left, with no tracking parameters within the URL, as normal. This is proof that the tracking parameters are never seen by the robot – if they were they would become part of the free search URLs.

This might take a couple of seconds to get your head around. Try looking at it this way :

Do we really imagine that a search engine spider crawls into its own PPC listings, and follows those URLs into the target site? After all, this is the only way the spider can ever see the tracking URLs. Were this to happen the clickthrough rate would be grossly inflated by the spider activity.

Track away

So, go ahead and add tracking parameters to URLs that point to your site. You still need to be careful about the parameters within the site of course.