Talking to the wall

I envisage an online communication site that allows public communication with anything: you can leave a message for anything you can name. For example if you want to leave a message for "the wall" you type in "the wall" into the To: field on the site and write a message in the Message: field (along with links, images, video, etc).

Messages can be anonymous, or users can generate an account.

Other users (or the same user) can post follow-on messages to each message.

The site can show all messages to "the wall", but would also provide contextual links to other message recipients e.g. "the Berlin wall" or "the wall in my basement".

Why would people use the site? To express themselves. To hide messages for people. To rant at a nameless bureaucrat or a bad driver. To communicate with a group of people who have not yet organised as a group.