First, many EU citizen tend to assume $1 is 1€ at first approximation, while currently it's more like $1.3 for 1€. Cthulhoo may have made this approximation. Second, lower salaries may be compensated by a stronger welfare system (public unemployment insurance, public health insurance, public retirement plan…). This one is pretty big: in France, these cost over 40% of what your employer has to pay. Third, major cost centres such as housing may be cheaper (I wouldn't count on that one, though). To take an example, I live in France, and here, entry-level programmers with an engineering degree make about 23k€ in net salary (often with a few benefits, and possibly more in the capital). That's about 38k€ that your employer have to pay. Convert that in US$, and we're talking about $49k.

Just to clarify: I did adjust euros to dollars in my estimation. To be more precise, I work in what is mainly a software company (though I'm not myself a programmer), and the standard net salary here is 19K€ per year which makes roughly 25$ per year. Now, of course if you're really good you can climb the ladder, and there are possible bonus if you reach outstanding results, but this requires more then the "teach yourself programming" level. From what I know, this is pretty much the standard, and a quick google search gives some confirmation of my numbers on this page: http://www.worldsalaries.org/italy.shtml.

It should be noted, though, that all salaries are rescaled roughly in the same way, and the cost of living is lower, so you might need to adjust your usual perspective.