I would be interested in creating distributed business systems without a central server. A Distributed Hash Table as used in p2p programs looks like the most promising storage solution. Are there already (open source) applications doing this? And if not, why not?
[after first response] There doesn't seem to be much happening after 2005. Are there any inherent problems with DHTs? I would think having fast access to scalable amounts of replicated storage would be interesting.