The beginning of the "World Wage?" I believe the concept you describe is outsourcing and people have been worrying about that for years. Amazing how predicting a little doom can garner head nodding though.

For me the market that is most open to being outsourced is web development. I happen to love developing web applications, always have. From the dynamic languages to the openness to just about every detail, I love it. I also happen to have a Computer Science degree. It's a lonely place being a Computer Scientist working in web development. Nearly everyone I've ever worked with has a career path like this:

1) Messed around with HTML. Copy and pasted some "DHTML" scripts and was blown away by how easy it was.

2) Picked up CSS. Became an overnight "separation of concerns" advocate and part of the dedicated few that "gets it"

3) Picked up PHP and MySQL in a week, built a dynamic web app. Became "multi-skilled," a "fast learner" and a "jack of all trades"

4) Became a professional developer, out-earning just about everyone they know, including people who have spent decades in their career

5) Years later, still does everything in the same LAMP stack and honestly believes that they should be working at Google if only they would be given a chance.

And the best part is that within 2 years of those people going through that, there will be someone with exactly the same background except update the technologies to the one dominating the blogosphere. I had to experience self-taught programmers come in and be all arrogant and condescending about Perl code simply because they picked up PHP or Ruby on Rails or Prototype in a weekend and it was much easier to grep. They all have the same stories about being frustrated that no one they work with seems to "get it," no clue that a Django/PostgrSQL/jQuery guy is coming right round the corner to make them a dinosaur.

The arrogance and delusion of these people, particularly self-taught people who have this mindset where they are superior because they didn't even NEED to go to college to learn what some guy with a CS degree did. Hell, the "head of software development" I used to work for used to tell a story about how he interviewed for Google and the first technical question they asked him was "what is 2 to the power 10?" and he didn't know and that was that. He told me this story like "look how random it is - that's not even related to coding, I mean who would know the answer to that off the top of their head?" and laughed it off like "google so crazy." When I replied instantly that 2 to the power 10 is a megabyte, he would neither tell that story nor confide in me again.

Point is, web development has been THAT easy to get into for years, and it still is. Even when it gets tough, generally the answer is "memcache" or throwing another server at it - luckily the places where quality is that little of a concern tend not to need more than two or three servers anyway. People talk about some Russian high school student outbidding them on odesk for a Wordpress installaton like it's some sign of things to come, but is that supposed to be a bad thing? Or should we be more concerned about the fact that people who know just enough to tinker with Wordpress for a living can earn more than doctors and nurses?

As for my job being outsourced, I left that web development company I worked for and now work for Nokia. I am specialising in JavaScript, a language that I used to love but then got pushed out from when a bunch of HTML/CSS guys picked up jQuery and changed their titles to "Front End Developer." Fortunately at Nokia, when I need to build applications that run fast on a mobile phone like the N900, neither jQuery nor throwing another server is the answer. So, honestly? I'm not worried.

TL;DR: the only people that need to be worried about a "World Wage" are people whose knowledge or expertise can be picked up in a week's worth of "PHP/MySQL for dummies."