As recently (re-)suggested by Kaj Sotala, posts now have much larger effects on karma than comments: Each up or down vote on a post is worth 10 karma.
Negative votes on posts have had karma effects all along, but for some reason Reddit's code imposed a display cap (not an actual cap) of 0. This violates a basic user interface principle: things with important effects should have visible effects. Since this just got 10x more important, we now show negative post totals rather than "0". This also provides some feedback to posters that was previously missing. Note that downvoting a post costs 10 karma from your downvote cap of 4x current karma.
The minimum karma to start posting has been raised to 50.
Thanks to our friends at Tricycle for implementing this request!
Take as a sample some of the people who have made nonmeta top-level posts in the past week or so and aren't super-regular posters. I count Shalmanese, David Balan, Matt, Mr. Hen, Warrigal, and JHuffman. A few of the posts I downvoted, but none was so abominably stupid that the person involved should be ridden out of town on a rail.
I looked up how long it took each of those posters to earn their 20 karma/50 karma based on comment points alone (not counting comments replying to their own posts). IE, how far do you have to go back for all comments between then and now to total >20/50 karma? It was quick and involved a lot of skimming and mental math, but it was something like:
If these numbers are representative of people who aren't super-regulars but like making top-level posts, they're getting comment karma on other people's posts somewhere like five to ten per month.
That means it takes someone with their usage habits 2-4 months to get 20 comment karma and 5-10 months to get 50. It also means that if one of these people's first posts made a dumb mistake and got them voted down to -5, then at 50 point threshold it'd take another 5-10 months for them to be able to make their second.
The cost of having too low a threshold is that there are a few dumb posts that never get promoted to where anyone can see them anyway. The cost of having too high a threshold is that we miss out on interesting information and the community doesn't expand.
Lower the posting threshold back to 20, and maybe do something about first post downvotes.