I am working on a multi-platform app (Mono) that will store text in a centralized location on the web and synchronize this text across clients that could potentially be IPhone/Android/WP7/OSX/Windows(WPF)/Linux/Web. I need to support some degree of rich text (at minimum bold/italic/etc./basic lists/alignment), and I am trying to find a format that will be easily displayable and editable across all these platforms (though I'm using Mono, the GUI will be implemented with the native toolkit for each platform), so far I can only think of HTML or RTF, neither of which sound very pleasant.
Thanks!