Using BBCode for formatting your postings, you can add an abstract, a short summary, to your postings.

Especially in the case of Twitter (and other length limited networks to which Friendica exports your postings via the API) Friendica will try to automatically decide which part of the posting is relevant. But often you as the author of a posting knows better.

In other parts of the Fediverse, the abstract will be used as content warning. In this article, you will learn how to add an abstract (content warning) to your postings and how to add one abstract for the different audiences. Friendica will also collapse the posting and show the abstract in addition to a button to open the text by default.

To add an abstract to your posting, simply put the text for the abstract within the BBCode tag at some place into your posting.

[abstract]This is the text for the abstract[/abstract]

This is the [i]normal[/i] content for the posting. With a link [url=http://example.com]to example.com[/url] and some other text.

You don't have to add the abstract at the beginning of the posting. You can also first write the posting and then add the abstract BBCode block at the end of the posting, when you know what you have written about.

If you add an abstract, this will used for all occasions of it's usage. As short version of your text that is exported to e.g. Twitter. And platforms like Mastodon, Misskey or Pleroma will use it to hide your posting behind a button, so that users may decide if they want to read the entire posting or quickly scroll by.

But, what if you want to have a different short version of your posting exported to Twitter, and use a very short list of words for the content warning for your followers on Mastodon?

To realize this, you can put more then one abstract section into your posting and apply an additional parameter to it, to specify the platform this abstract should be used for. This parameter is either a shortened form of the targeted platforms name or the protocol used. For Twitter the value for this parameter is twit and for ActivityPub platforms it is apub. Developers for connector/addons can define the expected value of the parameter for their connector. So, expanding the above example.

[abstract=twit]This is the text that is send to twitter.[/abstract]
[abstract=apub]silly content, some words of warning[/abstract]

This is the [i]normal[/i] content for the posting. With a link [url=http://example.com]to example.com[/url] and some other text.

From this posting, Friendica will export

This is the text that is send to twitter.

over the Twitter connector. And on Mastodon your followers will see

silly content, some words of warning

as preview of the text and only when they click the button to expand the full posting, they will see

This is the normal content for the posting. With a link to example.com and some other text. http://example.com

If you are replying to a posting that is using an abstract (or content warning) you might consider using this abstract as well for your reply. In order to have this done automatically you have to activate the feature in your user settings.

You'll find it at Settings → Additional Features → Post Composition Features → Add an abstract from ActivityPub content warnings.

In your user settings, you can decide what should be done with content warnings from other platforms. They either be shown as a title of a posting, or the posting can be collapsed in the same manner it would be when your content filter was triggered.

You'll find the setting at Settings → Social Networks → General Social Media Settings → Enable Content Warning.

Abstracts / Content Warnings are usually not applied to the stream of a Friendica user. The reason is, that Friendica offers various addons to filter the network stream according to the needs of the users. E.g. a simple word filter (NSFW), the advanced content filter or the language filter.