We already have published native iOS and Android apps, consuming the REST API data of our Ruby on Rails app-based backend. Source code for the feature and UI-complete native Android app is available as a development reference for the app's design, UI, and backend API.
The initial scope of the project will be a simple clone/port of our existing Android app for web usage, with an initial limited release incorporating basic functionality and further releases adding the more advanced features.
Our eventual plan is to completely replace the legacy browser based site with the web app, and possibly to then replace the native apps with native ports of the web app. This means that development should take into account both the design needs of web based clients (browser compatibility, SEO, etc) and potential portability into a native app.