In a concise little nutshell Google website optimizer allows for A/B testing of on page elements to determine effectiveness.  It does so via Javascript writing of page elements (thus my assertion that is has not real SEO bearing), and then tracking of conversions.  An awesome tool for Internet marketers given the price (free). If you have not seen it before, and would like to do some testing of your landing pages, give it a try.

   preg_match_all( '/google.com/search?q=([^&]*)/i', $_SERVER['HTTP_REFERER'], $match );
   $keywords = urldecode( $match[1][0] );

Your junior PHP programmer should be able to implement this without even trying to decode anything.  Actually, your junior PHP programmer should be able to take this snippet, and with very little effort extend it to all of the major search engines so that you could see not only what the user searched on to find your site, but also which engine they came from.

Now, you might be thinking… “whoop-de-do, how does this help me?”.  Well, ever thought about targetting affiliate links to users on your site?  Your programmer (yes, the junior programmer), should be able to take the keyword, and with little effort drop in a few related Amazon product links.  Or EBay links. Or other large brand affiliate links.  I say large brand, because you will want a program that can return related products for a wide range of search keywords.

Half of the battle to earning affiliate bucks is getting the right offer in front of the user. Well, the half of the battle is largely addressed with this. 

So my formal education is in economics. My best comparison of economics to this question is that economics is very much the attempt to put logical true versus false comparisons on a touchy/feely situation. The best (neh worst) of both worlds. And that is exactly why I went the econmics route in college. I very much like to see things in a true versus false world, but I have a strong yearning for touchy/feely.

Back to the original question though, the answer in my mind then is that I think it is best to be a combination of both marketer and programmer, if you already have the programming skills. If you are starting from the programming side and can bring yourself to open your mind, build up your marketing skills. However, if you are on the marketing side…. find a good programmer. The Internet is littered with people who tried to leap into programming from another side (ie, designer, marketer, even content writer). I read your code when I get contracted to either add features or fix bugs on the sites you’ve written. I see all of the security holes in your code (I would not exploit them except in a proof of concept manner, probably). When you are capturing user data, and as such are assumed to be protecting that data, you need to know what you are doing — leave that work to the professional coder.

Programmers — you need to read more, start to learn about Internet marketing, SEO, and monetizing websites.