We hear a lot how CTR is an important part of quality score, which can affect click costs and therefore ROI, thus adcopy can be optimised on a click through basis or (quality score in some advanced systems). This might be the right thing to do for some campaigns, but does looking at CTR go far enough.

Perhaps a company relies on driving leads to a call centre or promoting a phone number. Surely, you'd be better having a low click/impression ratio. Generally, for brand awareness campaigns, usually bought on CPM basis, the lower the click through rate, the lower the equivalent CPM (eCPM).

Take Adtext. Adwords, for example, 'optimises' ad serving to deliver the 'best' performing adtext, which considers the quality score; keyword cpc, relevancy, history, ctr....etc. After a period of time adcopy can become less effective, in terms of response rates, as people get used to them and have moved onto those of your competitors. In order to prevent this adtext fatigue, it's sometimes preferred to add new versions of ad copy periodically to challenge the quality/effectiveness of the existing ads. Systems, such as Adwords, will test the new adcopy and display more often if it proves more effective, in due course.

However, you have to ask yourself, is this the right thing for your business. Unlearn what you've learned - even from the search engine accreditation courses themselves. By rewarding a good CTR, the search engines are using less impressions or ad space to generate more revenue, so this benefits the search search engine primarily.

Search marketing is not necessarily about getting the best CTR/quality score, but picking the right SEM strategy for your business objectives.

If your business sells widgets and has a cost per acquisition (cpa)/ROI strategy, surely you want the highest converting or most profitable ads appearing more often - not necessarily the most clicked. In some cases the well responded adtext, might be over promising, so the CTR could be high, yet the conversion may be low - thus the roi is low and the cpa is high. This wouldn't be a successful result, given your business/SEM strategy. Perhaps your adtext isn't going to the most effective landing page - which isn't uncommon - and click through would not be an effective indicator. Looking at ROI/CPA would give further cause for investigation.

By implementing tracking scripts on your site and hooking up to the search engine via API, you can determine ROI and CPA, not only for your keywords, but also your adtext - and across all search engines as well!

Using BidFluency at WebCertain, we analyse which Adtext led up to the sale as well as the adcopy that referred the sales directly. Perhaps you tailor different styles of ad copy to searches at various stages of the purchase cycle. For example, if your targeting people searching for 'widget information' and people searching for 'buy widget' then perhaps the tone of your copy should be adjusted accordingly. However, most conventional bid management/tracking systems, will only attribute the sale to the first or last referrer. As you probably know, search is not as straight forward. Searchers are people, not clicks or traffic and behave in a wide variety of ways. If someone searching for 'widget information', they are in research mode, thus are likely to click on your adcopy, look around and make no further purchase and leave to investigate further suppliers. It is possible that, after the research has been done, the searcher refines the search at a later date to 'buy widget', clicks on your adcopy and make a purchase. The first keyword/ad combination was the first referrer or the 'assist'. The last referrer was directly responsible for the conversion, however, we identify which adtext also drove the assists and apply a more 'weighted' approach to your bidding strategy.

Don't get blinded by CTR optimisation, consider your business objectives and let them guide your SEM activities. Should ROI/CPA be most relevant, in optimising Adtext for e-commerce sites, don't just optimise the adtext that converts - searchers are not clicks, but people - as other ads might have contributed in attracting and acquiring customers for your business, so don't ignore the conversion assists.