Scratch

I would like to propose that everyone has a 'Personal Sandbox', which would function much the same as Wikipedia's 'Sandbox' works; a page where a user can write text and view formatting and test Scratchblocks before actually posting. The Sandbox is saveable and private, allowing one to test out long posts and work on them until complete.

Though one might argue that posts can be written and saved in a text editor and previewed through Previews, it is also important to note that Previews are not saveable and anything local to one computer may be inaccessible on another. Instead, Sandboxes allow a person to work on a post indefinitely and everywhere.

This would also let one finish a post privately, allowing you to keep your work secret until it's ready to be shown. Some might say that things like private Sandboxes are too much like private messages and against the transparency of Scratch, but the Sandbox poses no real threat to transparency, as this can only affect one person and thus needn't worry anyone.

In addition, Sandboxes would help those who use a device without a local text editor and could be unable to write about something or possibly write down their ideas. I believe Sandboxes would be in general just a good feature for Scratch to have.