EthereumWall.com is an experiment in using the blockchain to provide a secure unmoderated decentralized message board.
Message posts are permanent. There's no server-side logic, all transactions and calls are to/from the Ethereum blockchain directly, meaning that anybody can deploy their own wall or create their own viewer app to interact with the message board.
The frontend supports markdown syntax and code block highlighting. You can also sponsor posts with Ether to highlight your messages (or to claim the sticky "Top Sponsor" slot at the top!) There's some functionality in the contracts that I haven't built into the front-end yet (an open directory for multiple public boards, the ability to gift ether to posters when you "like" messages) so I'll evolve the front-end over time.
Suggestions and feedback welcomed

Play with it using a web3 enabled browser here:
EthereumWall.com. View the source code here:
EthereumWall.com/tech.html
Comments
This simple aspect is what is missing severely everywhere; namely how does one get to and use these dapps.
This explained on Windows and the ability for everyone to use and try it and actually see the results like what is currently written on your wall and viewable in a regular browser will boost adoption 1000's of percentiles.
The MIST browser I have installed on Windows. Looks nothing like the earlier versions on the old videos and screen shots, there is no address bar and there is no way to navigate. I do recall (maybe) playing with earlier pre-latest Mist, AlethOne and Zero and there may have been a means to navigate within there?
Key is for all the noobs and non-techs including myself, the wall says you need to browse using Mist. Right now I see no way of doing that.
If we can give a step by step simple instruction how to do this, and how to interact with dapps, we will solve 99,99% of everyone's problems; that is no one actually knows what Ethereum is or does.
I think your wall can be the stepping stone for all us clueless, if we can navigate as per instruction using mist, leave a message on the wall, then show friends and others, via regular browser, what has occurred, it would benefit Ethereum immensely.
Right now there is a mish-mash of scattered disconnected information, examples, theories etc etc, no single 1, 2, 3, step instruction and demonstration - start to finish of actually using Ethereum and being able to see the result.
I am convinced your wall will solve this.
I know that ETH is still growing and on early stages but we are the community and we can do something to help others and ETH itself.
I agree that it could be a really good learning tool to onboard people to Ethereum. Learning how to use DApps and getting set up is really a big hurdle right now.
I'll work on adding a "how to use" page to cover the basics of getting set up. I do think we have a little way to go with the tech before it can really be adopted by the average user - the biggest issue being that even once you have the correct software set up, you still need to sync the entire blockchain to your computer before using it. Light clients will solve a lot of the issues, but for now clear guides are definitely hard to find.