In the 11 years that Reddit has been around, we've accumulated a lot of rules in our vote tallying as a way to mitigate cheating and brigading on posts and comments. Here's a rough schematic of what the code looks like without revealing any trade secrets or compromising the integrity of the algorithm. Many of these rules are still quite useful, but there are a few whose primary impact has been to sometimes artificially deflate scores on the site.
Unfortunately, determining the impact of all of these rules is difficult without doing a drastic recompute of all the vote scores historically… so we did that! Over the past few months, we have carefully recomputed historical votes on posts and comments to remove outdated, unnecessary rules.
Very soon (think hours, not days), we’re going to cut the scores over to be reflective of these new and updated tallies. A side effect of this is many of our seldom-recomputed listings (e.g., pretty much anything ending in /top) are going to initially display improper sorts. Please don’t panic. Those listings are computed via regular (scheduled) jobs, and as a result those pages will gradually come to reflect the new scoring over the course of the next four to six days. We expect there to be some shifting of the top/all time queues. New items will be added in the proper place in the listing, and old items will get reshuffled as the recomputes come in.
To support the larger numbers that will result from this change, we’ll be updating the score display to switch to “k” when the score is over 10,000. Hopefully, this will not require you to further edit your subreddit CSS.
TL;DR voting is confusing, we cleaned up some outdated rules on voting, and we’re updating the vote scores to be reflective of what they actually are. Scores are increasing by a lot.
Edit: The scores just updated. Everyone should now see “k”s. Remember: it's going to take about a week for top listings to recompute to reflect the change.
Edit 2: K -> k