I think that what software you use has little to do with scaling a huge site. The biggest obstacle is how your data is organized and accessed. This is different

I think that what software you use has little to do with scaling a huge site. The biggest obstacle is how your data is organized and accessed. This is different for every application. If you can't get the data schema right then what software you have doesn't matter. That's assuming you're huge. If you're not huge then just build something and don't lose focus trying to build something that can handle 100 million users when you have 100.