GPL post-dates network software distribution (we got our first gcc via ftp).
Yes, but if you use open source libraries for your closed source SaaS - thats fine. People get their software _over_ the network delivered to them in a VM (your browser).
Yes, but if you use open source libraries for your closed source SaaS - thats fine. People get their software _over_ the network delivered to them in a VM (your browser).