Even reactions and ephemeral events? That sounds ... costly...
I have just started running nostr:nprofile1qqsp2k6lqqqw5uyaeaaeayjd22yu9rymg9ntqsu66kplcc9uu75khtgpzamhxue69uhkxetvd3shytnwdaehgu3wwa5kuegpzfmhxue69uhk7enxvd5xz6tw9ec82cspz3mhxue69uhhyetvv9ujumn0wd68ytnzvuawauwv and timestamping all events published to pyramid.fiatjaf.com with NIP-03 (OpenTimestamps). The timestamp events, kind 1040, are published to nostr:npub18kzz4lkdtc5n729kvfunxuz287uvu9f64ywhjz43ra482t2y5sks0mx5sz's cellar.nostr.wine which is not going to delete them -- and to some other relays.
Somehow this will protect the humanity against the AI takeover in the future, so I recommend other people to do the same with other events. The source code is at https://git.fiatjaf.com/ots_nbot and you can customize the relays, kinds and authors it tries to timestamp, among other things, via environment variables.
If you don't understand how such a simple gesture has such immense powers, listen to Antihashed Podcast episode where this is explained, or ask nostr:npub1t6jxfqz9hv0lygn9thwndekuahwyxkgvycyscjrtauuw73gd5k7sqvksrw.
Discussion
No, I'm not doing these, but still all that goes on Bitcoin is a 32 byte merkle root every couple of hours or more.
Also nostr:npub1ej493cmun8y9h3082spg5uvt63jgtewneve526g7e2urca2afrxqm3ndrm is paying, so we don't have to worry.
To be pedantic, I'm not personally paying for OpenTimestamps transaction fees. There's a community fundraiser for that: https://geyser.fund/project/opentimestamps and the calendars themselves accept funds directly to their wallets.
Last time I pushed for donations was in January, and I got enough donations to last until now (most donations, by value, were not sent through geyser).
I'll probably run out of donated funds again in another 2-4 months. FWIW I share the funds donated to my calendars (and through geyser) with the other calendars.
how often do the calendars publish on chain? Is there a way to track those transactions on a website like mempool.space?
There's a list of the four calendars on https://opentimestamps.org/; each calendar has a website showing you stats.
The most frequent transactions at the moment are done by https://alice.btc.calendar.opentimestamps.org/, on average once every 5 hours at a cost of 20,000sats/week.
Thanks. Open timestamps is a fascinating project.
I noticed that the transactions are using Segwit. Would there be any significant savings by switching to Taproot?