Subtle changes, bugs and feedback

We can definitely improve this, but there are limitations and catches.

1. If we make it incredibly accurate then it's slower (i.e. we send it off to the server and do the processing and deliver to you what the server will do)
   
2. If we make the server do that work, we will still only do 80%... the last 20% are the embedding, mentions processing, which are currently done after you post it as some things might be slow (some embeds require us visiting a third party server for info)
   
   

We had the choice to deliver a client side preview that is a good approximation of the capabilities of the server and deliver a real-time and instant preview (it's done on your device).

Or, to deliver a highly accurate preview and potentially introduce a lot of lag (a 1 second round trip including processing) for every time you press the preview button.

We chose high speed and no lag, as that is the more pleasing experience. We accepted the downside is that all of the edge cases will be posted, and then subsequently edited... which isn't a great experience, but we hope fewer people experience this, and only then during the acclimatisation phase (which has only affected this forum which we've imported).