Unlike many web editors in existence, Thimble isn't an icon-laden drag 'n drop fest filled with context sensitive property panels and menus. Rather, Thimble offers a simple notepad-like environment where coders can bang out their HTML while they view a real-time, instantaneous preview of their work. When a user finishes, they can publish their efforts in a single click for all to see, complete with hosting and a link.
In short, Thimble seems ideal for the up-and-coming coder who wants to play with HTML tags and style sheets in a web-based sandbox. Alternative, it also sounds perfect for anyone who wants to make a quick 'n dirty example to help others (i.e. the many helpful people on our forums)
If you're thinking about using Thimble to create your own web page or website though, you should definitely reconsider.
Why? Well, first and foremost, Thimble isn't a finished product. Since the current iteration is merely a test run, anything goes. Secondly, although Thimble makes it super easy to type out and publish your web-based masterpiece, its current form isn't quite conducive to hosting an entire website.
For example, when you publish a page, you receive a link to share with others (e.g. http://thimbletest.org/p/4fn). If you want to edit that page again, you merely need to add "/edit" to the end of its URL like so: http://thimbletest.org/p/4fn/edit. Next, when you save your changes, you receive a completely different URL, like this: http://thimbletest.org/p/4dl.
Now, you have a copy of your old page, a copy of your new page and both have different addresses. This actually may be intentional behavior -- it makes it seemingly impossible to maintain valid links across a multi-page site. There is also the issue of deleting pages: there is currently no way to do this, aside from contacting Mozilla support. As you can see, Thimble is definitely intended for single pages.