Toni responded on Bluesky. I couldn't fit my reply in 300 chars, so I wrote it here.

Toni, thanks for responding. Lot of food for thought here.

My main interest is text, I want to be part of a network on the web that allow us to write text in one place and have it show up anywhere a person wants to read it.

Think of it like podcasting, which ends each show with this -- "Tune in Wednesday wherever you get your podcasts." This imho is why podcasting has remained unowned, where we can't say the same for what blogging has become.

I think the standard.site project shows how it should work inside the AT Proto world and we can use RSS 2.0 to bridge to the rest of the web. The value you have here is a consensus among a few developers as to how they want to work in the same space that Bluesky runs in, but in order for it to be more than a demo, imho, they have to have access to the millions of Bluesky users. Otherwise imho nothing will happen, beyond a demo of what could be, and that would be a waste. They're doing really good work, and other devs are watching. ;-)

Now to the questions you ask..

There's plenty of prior art in Facebook which has never had a character limit, and style and links are handled by HTML. Real text in a social media platform is very straightforward. And X is easing their character limit, and makes it possible for me to post something like this in their system, but could not post it on Bluesky.

Put a "See more" link at the end of the 300 chars, or 500 or whatever you decide on to show in the timeline, and when you click the link the lower border scrolls down ad the rest of the text appears. A vertical scrollbar could be used as well. (In FeedLand and RSS.chat we don't even include the "see more" link, just click on the text and it expands, click again and it returns to its default height.)

Now for the other types, pictures follow the same pattern. Cut the display off at the same point you cut the text off, and one click to see the rest, with no need to go to another site (a major impediment, people hate clicking on links because of paywalls, and other noise that you almost always get when you click a link. The web as it is has trained people that clicking a link is asking for a lot of questions and then you still don't get to finish reading the article. In this mode, you'd guarantee a peaceful transition, because you care about the user experience.

I would also like to see enclosures so you can do podcasting here too.

The other types you mention are great, you should be able to fit in too, but each would need their own UI design, and a bunch of trials, and search for prior art so you can learn from others experience. You're blazing a trail, which is good. This segment of the industry has been stagnant for far too long.

BTW, I explained my goal when I started this work at textcasting.org. The tagline is "Applying the philosophy of podcasting to text."

It really is that simple. Podcasting was built out of MP3, RSS and smartphones. This system, when we realize interop among platforms will also build on RSS and Markdown, imho -- it plays the role that MP3 played in podcasting. It's the payload. And people love markdown for its simplicity and transparency.

I think you have one of the most interesting challenges in tech now, and you have a good shot at pulling it off, representing the part of the web that wants to be part of the web as opposed to the others who want to be the web.