InstaBlogg allows you to create one-time-only blog posts, without logging in or setting up a blog. It’s the fastest way to write a blog post. No need to sign up for a blog, customize your theme, build your archive etc. Just start writing. When you’re done, you have a full featured, good-looking blog post, with commenting and social sharing options. You can then send your link to the myriad of web and social channels available on the web today.
How do I edit my post?
When you first save your post, you are given a unique web address to edit your post. This address should be kept secret, since anyone who knows this address can edit your post. Be careful not to lose this address, or you will no longer be able to edit or delete your post.
Is it anonymous?
Yes. We don’t require a signup and we don’t hold any information about you, other than what you write in your blog post. If you want to make an eponymous post, remember to add your contact information in your post. [source]