add access control options to public links

[Thibaut Brandscheid]

It would be really nice if UbuntuOne had some access control options for public links.

Suggestions:
- add 'name + pw' option for public links
- add 'stop publishing after N downloads'
- add 'delete file after N downloads/days'
- add an access control tab to the UbuntuOne Control Panel

Sharing files that are bigger then 4MB is still a problem for average users → http://xkcd.com/949/ . Having an easy possibility to share & control bigger amount of data would be very nice and doable through UbuntuOne. Right now UbuntuOne's 'Publish' option is too hidden and difficult to use. It would be much better to have a 'Cloud' button in Thunderbird's write mail window near the 'Attach' button that allows average users to add a link to a file from their UbuntuOne cloud storage. Here my access control idea comes into play...
This would solve the can't-share-big-files-bug that bugs people now for some decades. I haven't see any operation system that has right now a similar feature and therefore it could be a big plus for Ubuntu.

Two things:
1. Maybe make it a UbuntuOne pay-feature (if it is necessary because of high traffic).
2. The ultimate feature would be to have a service like this that is company independent (user hosted).