It seems crazy. I can't imagine Reddit without subs.
As an ordinary user, I thought that the creation of subreddits was a clever solution to the Eternal September Problem.
The initial pool of users were folks that were sniped away from Slashdot and Digg. There was quite a bit of frustration about the editorship of Slashdot, and having a system that was effectively user-edited was quite attractive.
But as the readership grew, a wider array of material started showing up, frequently accompanied by the typical grumbling about relevance.
The solution was to split off new user groups into more specialized subgroups. The initial set of subreddits were effectively curated by Reddit itself, based on the categories of stuff that was showing up in practice. User-generated subreddits didn't come until later.
Everyone wanted tags for posts (myself included), and when they announced subreddits, there was a lot of belly aching. I thought the choice of using subreddits was a technical one to make the site more easily partitionable but they gussied up the reasoning behind the concept of communities. I think they made the right choice.
Some folks complain about the Digg debacle and how that negatively affected the Reddit userbase, but IMO what truly fucked Reddit as a tech news source was the introduction of images.
A knowledgeable, enthusiastic community provides lots of background, alternative views, tit bits of related info and random facts. Without comments and discussion most of the value is gone.
I mentioned this merely as a historical footnote to show how far reddit's come.
Reddit didn't even have comments at first!
https://web.archive.org/web/20050804002153/http://www.reddit...
I've used my account to comment since before they added subreddits. And I never stumble across one of the "toxic" ones except for the rare occasions when one of the other subreddits links to those ones.