Also interesting to include Digg and reddit. If you extend the date to 2014, turn reddit off because you won't be able to see anything other than green, up, and to the right.
Not in the beginning. There used to be a site that measured the time between when a story got to the homepage of slashdot vs. Digg. It was a tossup for a while but eventually Digg started winning out which is when I stopped reading slashdot. Then when Digg started to get inundated with non-tech related stuff, I switched to reddit which was mostly tech focused at the time (see [1]) and once that started to get filled with politics and other garbage, I finally found and switched to HN.
The same happened to Digg and reddit. Digg started lagging behind reddit (things would show up on Digg's front page an hour or two after they showed up on reddits'), which then started lagging behind HN (at least r/programming).
Oh man, I remember when Digg had their big redesign snafu and reddit exploded and basically became the place it is now. Right in the middle of 2010 [1]. To me, that was the final nail in the coffin of the reddit where you could have good conversation and say controversial, if well-thought-out arguments without getting downvoted to hell. After that, memes and macros became the currency of reddit.
> After that, memes and macros became the currency of reddit.
You really have to sign up to the special interest subs. Of course /r/pics isn't going to be a place for good discussion. But there are hundreds (maybe thousands) of excellent, active, well moderated subs all over reddit that cater to just about any topic and they aren't hard to find.