Using local peers takes pressure off international and other long distance transfers, and is said to simultaneously increase file download speeds.
It is most visible as a plugin for the Azureus BitTorrent client - it is also available as an open tracker, and the Aqualab research group has recently published code to make Ono services easy to incorporate into other applications.
A more recent evaluation (one that used a single client connected to only one ISP located in the United States) has shown that Ono's benefits in practice are far short of the claims made in the original paper.
In particular, when downloading real BitTorrent swarms while measuring the end-to-end benefits of using Ono, performance is unchanged, and interdomain traffic is reduced by less than 1%.
The P4P project shares a similar goal to Ono, but requires co-operation with ISPs and the installation of "iTracker" servers to identify nearby peers.