Amir Salihefendic writes about programming, web infrastructure, and productivity, including how Hacker News and Reddit rank posts.
HN links it mainly for its explanations of the Hacker News and Reddit ranking algorithms, which commenters call detailed and useful.
Great comment! I did not watch that talk. But I did watch another talk by John Cleese on how to become more creative ( https://www.youtube.com/watch?v=kH8uYDJlwog - only 10 min). It's a very recommended watch as well. I especially like this quote:
If you're racing around all day, ticking things off on lists, looking at your watch, making phone calls, and generally just keeping all the balls in the air, you are not going to have any creative ideas. - John Cleese
A year or two ago I also did a presentation on how to become a more creative programmer where this quote is also included, the slides can be seen here http://amix.dk/blog/post/19599
Previous discussions:
http://news.ycombinator.com/item?id=1781013
http://amix.dk/blog/post/19574
The simplified algorithm is
Score = (P-1) / (T+2)^G
where,
P = points of an item (and -1 is to negate submitters vote)
T = time since submission (in hours)
G = Gravity, defaults to 1.8 in news.arc
The updated algorithm posted by pg has other factors, but those are related to quality control. If the same algorithm is still deployed, stories decline with time. So, during quiet periods, the new stories with far lesser number of votes rank higher than old stories with high number of votes.
I'm not sure how HN does it specifically. In a version of our app, we had scoring which was initially modeled after Reddit's algorithm (http://amix.dk/blog/post/19588). A server task updated the scores for every item every hour. We could have limited how far back we went, but had no need in our case given that the amount we indexed was within reason. We'd add or subtract from the score based on a set of rules that considered a number of factors including posted date, number of votes and number of comments. We had an admin tool for assigning more or less weight to the various factors.
Related to CloudFare, I know what a real CDN is, but I'm not sure what cloudfare does useful at all, ex:
http://halfelf.org/2013/i-dont-understand-cloudflare
http://pergento.wordpress.com/2012/02/01/cloudflare-slowed-down-our-site/
http://amix.dk/blog/post/19627
Like they tell you to use CloudFare w/ a CDN. what?
It appears that they are a good marketing company, and OK tech, but not clear to me what.
Compare it to real CDN Fastly or MaxCDN.
So other than marketing, what does Cloudfare do when you pay them?
As far as I can tell, it’s based on a combination of upvotes and time since posting. New comments start at the top of their tree and, as time passes, settle into where they would be if sorted by upvotes. So yours is above the other one because it’s more recent, but in a week, if the upvotes don’t change, the other one will be on top. It’s probably a similar algorithm to Reddit’s published “hot” algorithm (http://amix.dk/blog/post/19588).
For those who do not understand the Wilson algorithm, see this post which was on HN recently, explaining how it works in a little more detail: http://amix.dk/blog/post/19588
(I agree with other commenters that it is complicated and lacks common sense to average users, but I feel like I have a general understanding of the concept thanks to the above link)