As there are many heavy Twitter users in Japan, many Japanese are looking for alternative social media to Twitter.
Many seem to have migrated to Mastodon and Misskey, but as they tried different social media, some people liked Nostr, and they post here daily.
In particular, there are a lot of developers on Nostr who find Nostr technically interesting, and they also share their development status on TL, so you can see a lot of activity.