I will also be releasing code (there are quite a few decent APIs that can make this very easy to do - "centralized components") to access the messages from the Blockchain so anyone can easily add the code to their web-site (so if our site goes down - there will be another).
I had thought about creating some kind of interface/software to interact with the Blockchain and serve as a website would but through software. Not sure how you would get around the issue of having a central service wallet that funds it all (Unless messages get sent to my server and then the transaction is made, adding it to the Blockchain). A huge project I'd imagine.
I will be increasing the limit to 450 bytes per message soon - and through chaining you could have any amount of data you liked - but this is not my plan.
The only other issue really is that some trust has to lie with myself and/or the provider (I could reduce risk as much as possible by taking the necessary hosting measures - and then I would have as much control as possible - owning the main Bitcoin wallet [https://bitaps.com/1K69sEhUwNgiva3xzPnToxS89dzydU7nPm] means a lot) used somewhat as I could replace certain words with others or what have you! - but.. this can be randomly tested and would be apparent pretty quickly if it was to happen and people would stop using the service and probably jump ship.