{"id":698,"date":"2022-12-02T15:56:28","date_gmt":"2022-12-02T15:56:28","guid":{"rendered":"https:\/\/teaching.sociology.ul.ie\/bhalpin\/wordpress\/?p=698"},"modified":"2022-12-02T17:08:31","modified_gmt":"2022-12-02T17:08:31","slug":"pinging-mastodon-instances","status":"publish","type":"post","link":"https:\/\/teaching.sociology.ul.ie\/bhalpin\/wordpress\/?p=698","title":{"rendered":"Pinging Mastodon instances"},"content":{"rendered":"

Mastodon is less discoverable than Twitter, particularly because it doesn’t have full-text search, and because it has multiple instances. How do we know what’s going on, or which instances are particularly active?<\/p>\n

There is a webpage of instance data somewhere. That is a good starting point.<\/p>\n

But what about propagation of individual posts? How do they get seen, how quickly do other instances pick them up, which other instances? Here I summarise a quick experiment that exploits a feaure of mastodon software’s behaviour to map out some details of how a post is seen by other instances.<\/p>\n

It appears that as soon as Mastodon instances see a post containing an (as yet unseen) URL, they pre-fetch it. This has been causing a certain amount of controversy over the past few days as website owners have seen unexpected bursts of traffic.<\/p>\n

My small experiment: I a sent out test post from my account on mastodon.social, every 3 hours over 18 hours, each time with a fresh URL, and watched my web-logs. What did I learn:<\/p>\n

    \n
  1. Yes, there is an immediate flurry of GET requests<\/li>\n
  2. Of the order of 60 instances respond to any one post<\/li>\n
  3. 54 instances respond to every post<\/li>\n
  4. No instance responds twice to the same URL<\/li>\n
  5. If someone from another instance responds to the post (hi, @reliablyjeff@sciences.social) all bets are off<\/li>\n
  6. Some instances are very slow to respond: possibly because it is the originating host, mastodon.social responds within a minute to the first post, but takes several hours for the rest<\/li>\n<\/ol>\n

    Excluding the two waves where there people responded to the test posts, and mastodon.social, mean delay is 151 seconds, median 34.<\/p>\n

    <\/p>\n

    \u00a0Apart from mastodon.social, there are a few instances (mastodon.sdf.org, mstdn.ca, nonexiste.net) that sometimes take more than an hour to respond.<\/p>\n

    \u00a0<\/p>\n

    When people reply to a post, there is a new flurry of GET requests. These are presumably from instances that are checking out the replier’s instance, but not mastodon.social. I had one reply from mastodon.online, which triggered requests from the following list of instances:<\/p>\n