It would be really great if, when your post a link to a web page, you could have its summary and shared picture visible as preview in your diaspora post. Twitter and facebook are doing it and i think it’s a great (missing) feature diaspora* should adopt.
We already do this. If the page supports OpenGraph, you can just paste the link, submit the post, wait a few seconds, reload, and the preview will be there. 
Okey, i didn’t notice i had to reload the page.
It might be interesting to show the preview without needing to reload ?
While that would probably make the user experience a lot nicer, we don’t really have any “live updates” in the UI right now, and that would be a bit hard to implement in the current state. 
But it’s a fair suggestion, I changed the title to match that, so we can leave this thread here open for future discussions on this!
Your idea is going further than mine. That’s really nice.
Mine was only suggesting to render the view directly when posting, with no needs to reload the page.
But if the work is almost the same, your point of you is far better.