I have an idea for an app, it goes like this:
The app should be more designed for sites that don't require you to type in a captcha, unless there is a workaround for MU, RS, etc.
when the app is started it works like wiiXplorer (the file browser).
you search your sd card/usb drive for a text file containing the download links.
The app connects to the internet, and retrieves info for the file, if the file is down, it will give the message the respective sharing site gives when in the pc.
you click dl, and choose a file destination (unless you have it automated to go into a folder or root of a device (sd/usb).
the file downloads!
thats my idea, but it is a bit difficult to start with not much knowledge of GRRlib and other app building tools.
