I've notice, since I updated from WordPress 1.5 to WordPress 2.0 sending trackback to another blog doesn't work anymore (when I write a post and anter the URI in the "trackback" field).
Also when I publish a new post, it doesn't ping to Technorati anymore. And "http://rpc.technorati.com/rpc/ping" is properly entered in Options / Writing / Update Services.
Even a manual Ping doesn't seem to work (Ping / Update Ping)
I don't know if the trackback and the technorati ping problems are linked together, but does anybody have any idea why it is not working for me ?