Show HN: Free Reddit submission scheduling and vote potential estimation | Hacker News Reader

Show HN: Free Reddit submission scheduling and vote potential estimation

redditlater.com

43 pointsElvisMa17 comments

I don't understand the point of the analysis. A slightly higher percentage of things might be posted at 8:00 on Wednesday. That doesn't mean it's the best time to post. In fact it might be the worst time to post because you are competing with all those other people.

Here's a better analysis for HN: https://silverman.svbtle.com/the-best-time-to-post-on-hacker...

It measures the liklihood of reaching the front page at a given time, not the number of posts at that time.

Maybe I'm being cynical, but the dip at 4:00 pm makes me think there is some noise here for the Reddit chart. Also, the best time (8:00-9:00) immediate drops down to the average in the next hour, and then spikes again following that.

>In fact it might be the worst time to post because you are competing with all those other people.

I don't understand that reasoning. Yes you are competing with other people, but for a reason. Reason being, during that time a lot more people are active and that is why the chances are much higher to have a high scoring submission.

Isn't your reasoning the same as saying you shouldn't play the lottery using "dates"? Like anniversaries or birthdays. So numbers 1-31 etc because that is what everybody plays and if you win you have to split the pot with all those other people? To me, this is ignoring the fact that a million dollars split between 100 people is still a lot more than zero dollars you get for yourself because you played different numbers.

Perhaps, but it's not exactly a fair system. Reddit is based on a "rich get richer, poor get poorer" type model. The more people you are competing against, the more likely you are to end up in tail end of the distribution. There are only a limited number of slots on the front page after all.

No one sorts through the "new" tag, especially on reddit. So your post depends on getting on the front page for a few minutes and hope a few people see it and vote on it.

If there are many people posting, those precious front page slots will be taken, and your post will appear on page 4 and sink down over time.

Hence you are far more likely to do well in a smaller subreddit than a larger one. That wouldn't be true in your egalitarian model, where more users mean each post gets proportionally more attention.

But in reality those extra users still all go to the top 25 posts, but the competition to get there is increased.

>To me, this is ignoring the fact that a million dollars split between 100 people is still a lot more than zero dollars you get for yourself because you played different numbers.

The expected payoff of a lottery ticket minus it's cost, is already negative. If you divide up the jackpot it gets even worse.

Here's a (old) heat map I made of Reddit submissions average score by time and day-of-week of submissions: http://i.imgur.com/ur18gQa.png

Here's the heat map for only viral submissions: http://i.imgur.com/ct5LNcG.png

Subreddit behavior will typically match the first chart due to Law of Large Numbers. And almost all the time it will come down to luck so score prediction is misleading at best.

What I thought this was, and what would be fascinating, is a tool that you give both the post and context, and it predicts the response and posts it at the ideal time.

This could work by training an ML algorithm over the reddit corpus (especially the contextually relevant stuff -- the subreddit) and metadata (including post time, among many other factors).

Even more impressively, it could suggest modifications, ala crystalknows.com. Does anything like this currently exist?

> The reddit ranking algorithm is time-sensitive

Can someone explain to me why on earth they would do this? It just seems like they're throwing variables in a pot and coming up with ways to use them at that point.

I believe in this context it means that newer posts are ranked higher than older posts, which is pretty helpful in making sure the front page remains "fresh".

[0] http://amix.dk/blog/post/19588

[1] http://www.outofscope.com/reddits-empire-no-longer-founded-o...

As I understand it, it is time-sensitive but indirectly.

The number of votes compared to the age is important, but this isn't normalised compared to the current vote rate. There's a significant fluctuation in the number of people on reddit at different times of the day, so when you submit can be important.

This is absolutely correct. The algorithm is meant to quickly drop posts from the top. Such that even if a post has a record vote score, it still will only remain at the top for a few days.

The amix link above didn't load for me today, but I like this scienceblogs post on the algorithm.[1]

edit

It should also be noted that since reddit is open source, you can always dig right in! [2]

[1] http://scienceblogs.com/builtonfacts/2013/01/16/the-mathemat...

[2] https://github.com/reddit/reddit/blob/master/r2/r2/lib/db/_s...

not only that, the ranking is also defined by the overall activity in the sub-reddit it is posted in. So you can see a post with fewer upvotes, posted later over a post which has a lot more upvotes posted earlier. Which means, even submissions to very small sub-reddits have a decent chance to be promoted to trending and to r/all even

The trending or 'hot' algorithm is a bit different than the "top" algorithm.

I believe you're referring to the 'hot' algorithm which is meant to take velocity into account. Velocity tries to abstract away contextual factors like subreddit activity, number of votes, etc. and represent how quickly, relative to number of participants, a post is 'rising'.

The 'top' algorithm, however, is purely a factor of total vote (up - down) + time.

oh,... yes you are right :)

    cpdef double _hot(long ups, long downs, double date):
        """The hot formula. Should match the equivalent function in postgres."""
        s = score(ups, downs)
        order = log10(max(abs(s), 1))
        if s > 0:
            sign = 1
        elif s < 0:
            sign = -1
        else:
            sign = 0
        seconds = date - 1134028003
        return round(sign * order + seconds / 45000, 7)

here's the function in question, so yes a newer post with fewer votes than a minutes older post will remain on top.

I wonder how would this succeed when they have thousands of posts to schedule - each post will compete with the other. This might work when they have very small no. of posts to schedule.

frontrunning?

I can confirm that it is awesome, I use it for http://www.araprototype.com for a long time now :)

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