Wikipedia launched in 2001. Facebook launched in 2004.

The choice was narrower then. Ruby and Python, while already active, did not have nice web and DB frameworks (both RoR and Django started in 2005). Java was also much less mature, and even more wordy.

PHP, on the other had, was easy to get from any shared hoster.

There were many good web libraries/frameworks for Python before Django. One even had a transactional NoSQL object database.

Facebook does not "normal" PHP that much, they use host of languages, including Hack, erlang and lots of Python.

Most of their code is Hack, and Hack is a superset of PHP (last time I checked all it really adds is static typing and async)

https://news.ycombinator.com/item?id=14659729

> all it really adds is static typing and async

You make that sound like its not a big deal vs vanilla php.

It's really not. All the sadness and broken-ness of PHP is still there.

A lot broken-ness is still left for the sake of compatibility (especially since HHVM's open-source), but Collections and type hinting make a huge difference.

Right. That's why I said "Started With".

That Slack post is terrible. I can't believe they would site concurrency as a strength of PHP...."Asynchronously curl’ing to localhost (or even another web server) provides a shared-nothing, copy-in/copy-out way of exploiting parallelism." I almost have to wonder if this is satire

Well, Facebook and Wikipedia are using HHVM to execute their PHP code, so at least those two are not really satisfied with PHP. I bet they'd like to rewrite their code in a faster, more memory-efficient, language but are hindered by the complexity of their code base.

The OpenStreetMap website and editing API is written in Rails, not PHP. I think it was initally some other form of Ruby web application.

OSM started in 2004, but the editing API was ported to Rails in 2007ish.