Provide a means to upload/download a file while the application is in the background. Currently this is not possible on iOS at least because the session is not kept active when in the background. There is an article about this from ICS and how to do it with iOS here in terms of downloading at least:
Small files are fine as they download in time before the application stops some resources, but large files get hit by this issue. So being able to do it while in the background would be handy here.
Edit: Added that it was related to uploading as well as downloading as this was missed previously