I learnt a long time ago that people will happily click on totally irrelevant pay per click ads. For example, if you bid on “seating plan” I can assure you that a significant percentage of people searching for “boeing 747 seating plan” will happily click on your ad titled “wedding seating plan”. They won’t buy anything, as they aren’t interested in wedding seating plans, but you still have to pay for each click. You can stop your ad showing to these searchers by adding “boeing” and “747” as negative keywords. Problem solved.

But what do you do if you are selling software that only runs on Mac OS X? The vast majority of searchers are running Windows. Indiscriminate clicks by them could quickly turn your Adwords ROI negative. In your Adwords campaign settings you can choose to only show ads on desktop computers and laptops. But you can’t choose the operating system.

As discussed above, putting “Mac” in the title is unlikely to be enough. You can’t use negative keywords, because the vast majority of Windows users searching for, say, backup software will type “backup software” not “Windows backup software”. You can just bid on searches containing keywords “Mac”, “Apple” or “OS X”, but will this be enough? My general advice to Mac only software vendors was to avoid Adwords, unless the ticket price of their software was in the hundreds of dollars. But, as my software runs on both Windows and Mac, I didn’t have any data to back this up.

Recently I got some data on Adwords clickthrough rates for a Mac only app (www.puzzlemakermac.com) by Hokua Software. They have kindly allowed me to share the data.

Initially they bid on generic keywords, such as “crossword maker” and ran ads such as the following with “Mac” displayed prominently in the title:

The results from analytics: 60% of the people clicking on the ads were on Windows and 40% on Mac.

Then Google banned them from the word “Mac” in their ads (it is possible to get this reversed with the express permission of Apple, but I don’t know how likely they are to grant this). So they switched to “OS X” in the ad, which hasn’t been blocked (yet).

The results from analytics: 73% of the people clicking on the ads were on Windows and 27% on Mac.

Then they restricted their bids to Mac targeted keywords such as “mac crossword maker”.

The results from analytics: 23% of the people clicking on the ads were on Windows and 73% on Mac. But there was a big drop in the number of impressions.

I think it is going to be almost impossible for anyone to get a return from Adwords when the majority of their clicks have no chance of generating a sale. So only bidding on Mac specific keywords seems to be the way to go. But there will still be a significant number of wasted clicks from Windows users. Also any Mac users who don’t use the appropriate keywords won’t see your ad. Consequently the return on time and money invested is likely to be a lot lower than Windows, cross-platform and web developers can expect. If you have a Mac only product with: a high ticket price product, well-defined keywords and limited competition, it might be worth trying Adwords. But otherwise it is probably better to wait and see if Google release OS targeting.

Of course, you could always use one of the free Adwords vouchers that Google are handing out like confetti (I get one every month in my PC Pro magazine) and try for yourself. This is how Hokua software got the results above. If you do, I would be interested to know how your results compare.