Related to: Well-Kept Gardens Die By Pacifism.
I wrote a script for the greasemonkey extension for Firefox, implementing less painful downvoting. It inserts a button "Vote boo" in addition to "Vote up" and "Vote down" for each comment. Pressing this button has 30% chance of resulting in downvoting the comment, which is on average equivalent to taking 0.3 points of rating. If pressing the button once has no effect, don't press it twice: the action is already performed, resulting in one of the two possible outcomes.
The idea is to lower the level of punishment from downvoting, thus making it easier to downvote average mediocre comments, not just remarkably bad ones. Systematically downvoting mediocre comments should make their expected rating negative, creating an incentive to focus more on making high-quality comments, and punishing systematic mediocrity. At the same time, low penalty for average comments (implemented through stochastic downvoting) allows to still make them freely, which is essential for supporting a discussion. Contributors may see positive rating of good comments as currency for which they can buy a limited number of discussion-supporting average comments.
The "Vote boo" option is not to be taken lightly, one should understand a comment before declaring it mediocre. If you are not sure, don't vote. If comment is visibly a simple passing remark, or of mediocre quality, press the button.
And yet... the strategy your instincts are driving you to implement isn't making your karma go up fast. At least, it would go up faster if you lowered your standard. What your extra caution is achieving in practice is sacrificing karma gain in favour of conveying a reputation as a considered, insightful poster with a diplomatic style.
If you actually want to increase karma faster, post a whole heap more and only inhibit posts that are rude or particularly stupid.
That said, it is possible to maintain high karma and come across as an entirely unhug-worthy pain in the ass a lot of the time. Data Point: The most downvoted person on this site remained in the top posters list until a couple of weeks ago when I spent ten minutes browsing his posts making sure I that I downvoted everything stupid. By all means, I encourage you to continue to err on the side of not being a pain in the ass.
I'm still making comments. And I value some strategies over others to get karma - I don't want it to go up for sheer volume and dumb luck. I'd rather make comments that come to mind as good things to say, not just type the unfiltered contents of my brain. (The unfiltered contents of my brain contain a lot more fiction references, inside jokes that are known only to my close personal friends, and musings about muffins and tofu and broccoli than anyone wants to read.) And I'd rather the good ones get voted up and the bad ones get informative replies - no... (read more)