For Basecamp, probably the biggest compromise is that you can't upload files or photos from your browser. We're interested in exploring tools like PhoneGap (http://phonegap.com/) for smoothing over the missing functionality.
Ive been exploring phonegap appcelarator and rhomobile myself lately and have been settling more and more on rhomobile. Can you explain why you have been looking at phonegap instead? Im wondering if theres something about it i missed. That you.
A nice work around to the uploading files issue would be to piggyback your existing email solution. So after posting a message you could show a little "Attach files" link which would show an email address to mail the files to (or open a mail client if that makes more sense).
Mobile browsers don't support it. I've never been clear on the reasons, except maybe that there's a tension with the carriers over airwave bandwidth. Honestly: there's a Javascript interface in mobile Safari to access the location sensors and, IIRC the accelerometer, but the camera is offlimits.
On the other hand, the HTML interface is a mime-multipart form and a file upload - it's only convention that says "upload images only" - and the mobile platforms are very particular about access to files on the device. iOS for sure won't allow one app to touch the files of another.
Obviously at this point it is best used for applications that essentially provide a mobile interface to a web application that utilizes some of the advancements in UI design gained from the iPhone and Android generation of smartphones. Eventually I see the full gamut of APIs for things like camera, notifications, Geo tracking, etc. It will get more responsive too as people learn to use local storage to cache the app.
Well this is why people look at frameworks such as phonegap and appcelarator and rhomobile. They theretically give you the best of both worlds. Theres issues with them though including a lack of documentation for each of them. But as you say if you dont need to access the underlying hardware then theres almost no reason to not use html5.
