@Jenniferplusplus I sincerely hope that you aren't building Letterbook to only interact with itself and Mastodon.

Sooner or later, Letterbook will encounter content coming in from instances of software created by @Mike Macgirvin ?️, namely Friendica, Hubzilla (these two are actually older than Mastodon), (streams) or Forte. For reference: I am on Hubzilla.

You/it will have to expect and be able to deal with the following:

• Enclosed one-post-many-comments conversations instead of threads that consist of posts loosely tied together
• Permissions of all comments/replies firmly defined by the start post; permissions/visibility can't be changed within a running conversation
• "Monster posts" of any length because none of them has a character limit
• Not just Note-type objects, but also Article-type objects (from Friendica right now, the others may implement them once Mastodon introduces sensible support for them)
• Full HTML text formatting, up to and including numbered lists, tables, horizontal lines, character size and character colour
• Both quotes (as done in bulletin-board forums) and quote-posts (posts fully embedded in other posts like quote-tweets)
• Embedded links (this comment makes a whole lot of use of them)
• Inline images embedded within the text, and more than four of these in one post
• Inline audio streams embedded within the text
• Inline videos embedded within the text
• "Weird" mentions and hashtags with the @ or the # not part of the link (look at the mentions and the hashtags in this comment, then look at mentions and hashtags on Mastodon and compare them)
• "Summaries in the CW field" (because Mastodon repurposed StatusNet's summary field, which was used by StatusNet, Friendica and Hubzilla as an actual summary field, for content warnings in 2017; several Fediverse server apps continue to use it for summaries)
• All four support titles in addition to summaries

Some of the above may also come in from elsewhere, e.g. a wider range of text formatting than Mastodon allows itself to render is fully supported by just about everything that isn't Mastodon.

Also, ActivityPub is currently evolving. New FEPs are being put to use and bringing in new features far away from how Mastodon is working. In particular, (streams) and Forte and @silverpill's Mitra use decentralised identifiers as per FEP-ef61 (Portable Objects). Forte has nomadic identity fully implemented via ActivityPub while (streams) at least supports it. And all three have conversation containers implemented, silverpill wants to make them an FEP, and Hubzilla is planning to implement them with version 10.

This means three things. One, weird identifiers. Two, weird actor identities: What looks like one user automatically cross-posting to another account on another instance to non-nomadic ActivityPub implementations is actually the very same actor residing simultaneously on multiple server instances. Three, again, conversations work drastically different from Twitter and Mastodon.

Lastly, it may be a good idea to implement a little server type display from the get-go so that the user knows what kind of Fediverse instance something comes from. Misskey and its forks have it, Friendica has it, (streams) has it, Forte has it. Just because Mastodon doesn't have it, doesn't mean it's a good idea not to have it. Besides, if content from certain server applications malfunctions on Letterbook, users can pinpoint right away what server application causes that trouble when submitting a bug report.

#Long #LongPost #CWLong #CWLongPost #FediMeta #FediverseMeta #CWFediMeta #CWFediverseMeta #Fediverse #Mitra #Friendica #Hubzilla #Streams #(streams) #Forte #Conversations #ConversationContainers #FEP_ef61 #NomadicIdentity