DW: How significant is this move by Google to prioritize websites that have been optimized for mobile? Surely it's a sign of how Google perceives mobile devices and mobile marketing to be?

Tom Farrell: Absolutely. All the data suggests that consumers increasingly use mobile; it's their "go-to" screen. Around 50 percent of 18-34 year olds see the smartphone screen as their primary screen, certainly over the desktop, and all the data around Internet traffic backs that up. How significant the move is from Google's perspective is interesting, because I think it'll come out in the wash: They're right to make this public, they're absolutely right to do it, but how much impact it has on traffic statistics is to be determined.

But we have seen in the past that when Google has changed its algorithm that people or businesses have all of a sudden become "unfindable" - they used to be top-ranked on the first page of results, and then they slip back to the sixth page. Is that going to happen in this case?

I think it's unlikely that anyone will become unfindable - that's possibly a little dramatic! But they're guarding an experience and they're not delivering an effective product if I search on my mobile device and they give me search returns that are essentially unusable on mobile. So I don't know exactly how far down the rankings people will drop if they don't have a mobile optimized site, but I think Google are absolutely right not to send people to those sites - I can say that with confidence because we've got a beautiful mobile optimized site here!...[laughs]

Well, bully for you!...

… To be honest I think this is only a positive thing for almost everybody concerned.

To date, it's maybe been one of those things that's been put on the long finger [postponed] by some organizations, and the truth is they've probably been doing that and they've been misguided to do that, because the fact of the matter is that a huge number of the users or browsers of any business will be on mobile and smart devices. It's one of those problems you can't necessarily see, and by doing this, Google is - I suppose - raising awareness of that issue, and it suddenly matters and it matters more to a business.

So if a business does not have a mobile optimized version of their website, or both mobile and desktop versions, that's their own fault, is it?

Well, yes, in this day and age I think it absolutely is. It's so tempting when you look at everything with a design agency on a beautiful, large desktop machine, one of those fabulous large Apple monitors, and you forget that the man or woman in the street who accesses that site on a mobile - maybe over a poor connection on a mobile - isn't experiencing that. Like I say, it's one of those problems that sometimes is hidden, but you're delivering an appalling experience to 50 percent of your audience or more, and Google are probably doing the world a favor. Anyone who hasn't thought this through before, when they see their traffic drop off - and that was traffic they were only ever giving a bad experience - so I think Google are ultimately doing those businesses and organizations a favor.

They may be doing some people a favor, but Google is also using a certain leverage with their dominant position in the market. They've just faced anti-trust charges from the European Union, and again we're seeing Google using its position to force certain technological developments in the market, which, ultimately, will benefit their own business rather than other people's businesses - don't you think?

Well, I'm not sure I'm going to hang Google for looking to benefit their business, and regarding the anti-trust [issue], I'm not qualified to get involved in that. They guard closely the quality of their search product. They want to deliver the right results to the user, and if that user is on a mobile device, the right result is a site that can be viewed on a mobile device. And in many cases, sites can't be viewed on mobile devices.

And the technology is such that if I'm on a desktop, I'm still going to get a desktop version of the website…

Absolutely. A well designed site is designed to render differently on different sizes of device - that's responsive design, as it's called - so that you're seeing the best possible experience for the screen that you have.

Tom Farrell is vice president for marketing at the Dublin offices tech consultancy, Swrve. He is a mobile marketing expert.