In an early version of the proof of brain.blog website, the site used the @steemfiles account the same way Ecency uses the @ecency account to allow you to vote without manually signing every vote. I am not running proofofbrain.blog but the site www.steemfiles.com can allow you also to remove permissions.
The site steemfiles.com does not have a way to post, although you can vote and change permissions on both blockchains, sometimes even simultaneously.
Take a look at it here