First of all, I would like to mention the development team, who are doing an incredible job.

I would emphasise the ability to communicate seamlessly with different networks. Bluesky and Tumblr have already been mentioned. In addition, Friendica also communicates with the diaspora. A Fediverse network with around 700,000 users that they can't see with other Fedi projects.

My personal highlights

- import of RSS
- Groups (platform-independent discussion boards similar to Lemmy, Kbin or nodebb)
- Channel (user-defined timeline)
- Circles (to hold closed discussions with selected people)
- and the possibility to use many profiles under one account (for public, thematic or private use)
- relays (you may know them from Bluesky as feeds)
- the possibility to communicate with external people from Friendica via e-mail

Of course, the variety of possibilities makes the use much more complex than in other Fedi projects. In my experience, however, most new users get along very well with Friendica if they don't even know what the platform has to offer and don't overwhelm themselves ;)