Basically he edits the RFCs for Lemonade, which is a IETF standard for email on mobile devices. Basically it is a set of extensions for IMAP and SMTP that improve their performance over high-latancy low-bandwidth connections (like bad wi-fi or GPRS), such as forward-without-download and efficient re-synchronisation commands. Existing extensions such as a useful IDLE implementation are also used to push new mail notifications to the client.

To test the ideas in the real world there is Polymer. Polymer is a simple IMAP client that uses the Lemonade extensions as much as possible, so is ideal for mobile use. There is more: it uses ACAP to store the settings on the Internet (Dave also provides free ACAP accounts) so it's configure once, run anywhere. I've just tried it on my laptop, and it works nicely.

But it gets better. There is also Telomer, an email client using Lemonade and designed for Maemo. I've just tried it out, it may be seriously lacking in features at the moment, but it works. Features can be written over time, but it takes serious thought to get something as fast and usable as Polymer on mobile devices. I'll quote Dave:

That all said, once it's started, it connects to the mailserver over GPRS in about 10 seconds and pulls up the summary listing in 15, with a mailbox size of 2,882 messages. With a mailbox with 33,732 messages in, it's a little slower at around 25 seconds. That's still way faster than a desktop client on a LAN, of course, unless that desktop client is Polymer - in which case it'll seem remarkably slow.

This is what we need for a mobile email client. I know I've found my email client of choice on my new N800.

NP: Wish You Were Here, Pink Floyd