Once you understand Slackware, you realize it is really simple and stable. It comes with an excellent selection of software in the base install, and does not contain any “surprises”. I have had uptime in the 200-300+ days range on my home server, updates and security patches are quick and painless, etc.
In other words, it is a Linux optimized for usability and Unix compatibility, not necessarily user friendliness. It assumes you know what you are doing and gets out of your way.
It used to be BRIC (Brazil, India, China, Russia) or BRICS (same + South Africa). In the article, it has been extended again to other nations, therefore “so-called” because its membership is not the same anymore. Also, the membership seems very informal, it’s just a bunch of countries maintaining ties and having discussions, not a real group of countries, with its own set of rules and institutions.