Backup app via Rsync
A backup application is a must-have. Like a good image viewer (hint), i definitely believe it's one of the killer applications nowadays.
Comparing to DVD burning, online backup is the most handy and convenient way to do it.
I think a beginner developer could easily make the same sort of thing that look like the Ubuntu One service. All we need is a front end to Rsync. Also, for more security, the data would be send and stored encrypted.
I also think we can arrange a deal with a storage provider to make some money back to Haiku,inc (or HSA ;))
DataStorageUnit.com is one the the cheapest provider (2.99$/month for 100G) who use open standards.
Any other thought ?