RGTP is:
* secure (users are cryptographically identified)
* centralised (all discussion is held on one server under the control of nominated editors)
* linear (the item format helps regulate thread drift)
* mature (it has been in regular use for over fourteen years).

Yarrow is:
* convenient (it can be used on any computer which can run a web browser)
* stable (it has been in regular use on several sites for seven years)
* safe (all state is held on one server, rather than being passed over the net)
* free (the source is openly available, and licensed under the GPL).

The trunk is now reasonably mature, but branches will investigate:
* the use of template systems (see https://launchpad.net/yarrow/template )
* server development (now carried out at https://launchpad.net/spurge )
* the advantages of alternative storage systems in the server (especially flatfile versus relational database)

Contributions and expressions of interest are always welcome.

You can test-drive Yarrow at http://rgtp.thurman.org.uk/gossip/nettle/browse .

Photo of achillea lanulosa by Jim Pisarowicz, public domain.