[youngtaff]

How wrong can one comment be?

You might want to read this post on the founding of Varnish https://info.varnish-software.com/blog/history-varnish-cache...

And Fastly would certainly disagree that it’s only useful for PHP as they built a whole company based on Varnish

[perbu]

There are quite a few CDNs based on Varnish out there. Most of them are private, though, so you don't really see them.