Early reddit was a really fun place. Not sure how to explain it, but it kind of felt like one of those movie/cartoon mad science labs, but as a community. Basically everyone was an engineer, programmer, or scientist of some sort, or so it seemed. Most of the front page was science, tech, and programming news, and the remaining bit was people posting about tech gadgets and other stuff they made. It seemed pretty similar to HN, but more active and with a less market-oriented crowd just making stuff for the hell of it (which HN still gets a decent amount of).
Then people started posting pictures of cakes, political/religious discussions were everywhere, and it just felt weird. Digg was starting to decline and small waves of people started coming in, and once v4 launched and killed Digg, reddit's comment section completely changed, and the submitted content soon followed.
Now I go and see avatars and people buying gifts and gold (someone actually took an old 4chan joke and turned it into a business idea) and endless fake videos and random images. It looks like an absolute circus now.
People having been mentioning that finding niche subreddits is the answer, but in my experience, it's just a game of musical chairs. Virtually all of them get bad eventually.