The biggest problem? I'd say the biggest problem is browsers not fully implementing HTTP's REST support. Instead of having a different API for every freakin' we

The biggest problem? I'd say the biggest problem is browsers not fully implementing HTTP's REST support. Instead of having a different API for every freakin' website on the planet, we could use HTTP and actually implement GET, PUT, POST, DELETE. It's sad that it didn't happen in XHTML2, and also removed from HTML5.