When I joined reddit some 3 years ago, I was a Digg user that wanted fresher content. Eventually reddit's minimalist style converted me, since all the Digg content was showing up on reddit.
Coincidentally, I'm seeing myself frequenting HN more often to read actual content, instead of sifting through tons of memes and pictures. HN is also starting to display content faster, which doesn't really mean anything unless you like shouting 'First' in comment pages (even more so now that I'm working, so by the time I visit both sites, the stories are posted).
The community of reddit is nice, doubly appealing when you are having fellow celebrities among your members; however, with the influx of people, it becomes difficult to feel like you are actually contributing.
Honestly every community comes with its foibles. (Metafilter: kind of ridiculously liberal at times, overly anti-business, HN: not very good with racism/sexism (IMO), Reddit: kind of immature, dangerous libertarian streak) These are all awesome communities though (with reddit, the unit of community is the subreddit, rather than the whole site, and you do have to pick the right subreddits.)
I observed that also. I wonder if it's a flat cyclical fluctuation that popular public social news sites go through, or if it's a sloped cyclical movement (usually downward).
I believe it's just a function of how long you've been a member of the site - it's easy to fantasize about the "way things used to be", much harder to objectively rank the quality of a site and also keep track of that in your mind over time.
