Paul Prescod described why SVG is a good thing for his keynote address at SVG Open.
In a nutshell, SVG is a good thing because it is weedy. It finds new uses that its designers neither planned nor foresaw. As an open format, it is easily adopted in new and interesting contexts. (Paul talks about rumblings to make SVG a native raster format for printers, and cellphones that can display some interesting subset of SVG).
Forget the fact that it's based on XML. HTML is crufty, ugly, ill-designed and poorly supported (witness rendering incompatibilities across browsers), but it is weedy, and that's what's important. s/HTML/RSS/; and those statements are still true.
Perl is also a weedy technology. No one foresaw the advent of CGI, the rise of modules, the need for content management systems, or even XML integration when Perl5 was released. Yet Perl grew into each of those niches quite comfortably (and repeatedly :-).
The alternative is a "planned technology". C and C++ don't really matter any more. Why? Because they were designed to fit a specific niche: systems programming. You can do anything with C and C++, but neither language makes it easy to do new things, like web services, application servers, or even CGI. C and C++ aren't weedy anymore.
Paul argues that Flash is in a similar boat. It was designed for a certain kind of "multimedia" interaction. Its use is limited to those few areas where Macromedia designed it to be used. Sure, you could write a Flash framework for rendering vectorized maps, but why would you? Once you've done that work, there's still an uphill battle to reuse the Flash maps (in cellphones, send them directly to printers, etc.). You could expend approximately the same effort to render vectorized maps in SVG, and have a world of possibilities open to you.
