Currently, this bot just subtracts yesterday’s subscriber count from today’s, and give a percentage difference.

Current Algo: percentage difference in subscribers, averaged over the past 7 days. Where it’s showing less than 7 days, it’s because I don’t yet have the data (mostly because this bot hasn’t run for 7 days yet, but also because either it’s a new community, or because I had to fudge things a bit in the first few days by excluding communities with less 100 subscribers)

Edit to add: since the posts from previous days will always be available, the first filter for each new day is now how much a Community has grown in that one day. That is then added to earlier day’s, and averaged out.
Previously, it was just showing the rolling-average for every Community, but that meant that sites that had had crazy growth in one day but had now plateaued were still showing up and the list wouldn’t change until that aberration had aged out.

Please use this post if you’d like share better ideas of what constitutes “trending”, and if you have any preferences for how the posts are displayed. Thanks.