Tapio Sokura, OH2KKU, implemented the APRS precision and datum option (DAO) in the Ham::APRS::FAP parser last night. Looking at the IRC channel log, he started working on it at around 01:40 AM local time, and finished at 04:33 AM.
A few minutes ago I installed the new parser code on aprs.fi, so those of you transmitting uncompressed or mic-e packets with the DAO extension should now see the improved precision.
Compressed format packets have enough precision (around 1 foot) already, so DAO is not useful with it. aprs.fi properly decodes compressed packets (including speed and course), and compressed packets are the smallest ones (they help conserve valuable channel time on 144.39 and 144.800 MHz), so I would recommend using the compressed format instead of uncompressed or mic-e with DAO.
The only supported datum is still WGS84, no conversion from other datums specified by DAO is done.