I have an account on reddit as well, and my tone over there is different than my tone here. On reddit I make a decent amount of off-the-cuff remarks, occasionally troll a bit, participate in pun threads, and also have a decent amount of intelligent debate and discussion. Here I keep my mouth (fingers?) shut (stoppped?) unless I have something to say, because that's the vibe here.
Here, I'm more likely to vote people up who have a differing opinion on an issue, or even if they have an opinion that offends me, if they are able of stating and defending their position logically. On reddit, I'd probably just skim over their post.
Etc.
The tone of this site has gotten a little lighter since the first time I was here, and it seems to have gotten a lot more of a focus on the business side of things, which is fine - but if people aren't careful, the site will devolve into yet another pick-your-favorite-site-here.
So yeah. Please keep HN grown-up. It's nice to see mostly responsible discussion happening on a site like this, and I hope it continues to happen.