Did they just invent ETag or what? This "feature" is known for a few years and there are existing implementation, including this one: http://samy.pl/evercookie/ from 2010.

AdBlock/Ghostery helps a lot. But yeah, I agree that they have intruding ads. I guess there are not a lot of advertising companies that would allow advertising on such websites.

That's nice. You are comparing lightweight interpreter (PHP) to a Scala which runs on beast called JVM and consumes a lot more memory just to start and print Hello world.

You can literally run tens or even hundreds of small PHP websites on a 512 MB VPS or even a few larger. You also shouldn't forget about shared hosting, where most of PHP websites are hosted (albeit those are small sites, but they represent majority of all sites written in PHP).

Nonetheless, PHP language is improving and with the number of powerful web frameworks (Yii, Laravel, CodeIgniter, Symfony, CakePHP, ...) it's hard to not think about building a website in it. You get everything others have (MVC model, great ORM or other database layer, migration framework, etc.) and you can host it practically everywhere. It's cheap for testing and small sites, and reasonably priced for bigger sites.

Not everyone will create next Facebook, Twitter, YouTube, Google, ... so there is no need to argue scalability, because PHP is scalable and fast enough for majority of web applications. From security aspect, modern PHP isn't any better nor worse compared to alternatives.

Just let people choose whatever language they are most comfortable with or fits theirs needs.