I would also like expanations, because Facebook actually has a good reputation when it comes to their compiled languages engineers. Their C++ and D engineers built HHVM/Hack, their OCaml engineers built some great analysis tools and much of the supporting code for the HHVM/Hack platform, etc., the list goes on, so I'd like to know why someone would want to avoid their C++ library based on the "Facebook" name only.
Because Facebook also has a reputation of not playing nice with people, the rules, intellectual property, and so on. This is hardly a company anyone should support or trust and if you can't figure that out, I can't help you.
As far as their work on HHVM, it was necessary due to failure by bad technology choices from the start. There's very little interesting about this work unless you somehow love PHP, want to make debugging your production applications more difficult, and refuse to address your real problems. I am 100% sure no one outside of the PHP community cares about anything Facebook has done in C++.
Simply having a large company with lots of developers who might have even had good reputations elsewhere or even be smart doesn't mean much. Having worked in many places with lots of smart developers, I can tell you stories about too many geniuses in the room. Calling Facebook developers engineers is also about as apt as calling janitors sanitation engineers. We're programmers, or developers, or perhaps software architects at best depending on the position. I happen to have an EE and CS degree but given I do programming for a living, I'd hardly call myself an engineer. But we're way off topic :)
> As far as their work on HHVM, it was necessary due to failure by bad technology choices from the start.
HHVM arose out of Facebook's desire to save on server purchasing and operating costs. Facebook could run perfectly well without it on Plain Old PHP, but they'd have to buy and power more servers.
I'd hardly call PHP a "bad technology choice" given the outstanding financial success of many companies that use it.
