It’s easy for a non-Movable Type weblog to send trackback pings. They use a REST interface:
http://foo.com/mt/mt-tb.cgi?tb_id=ID&title=TITLE&url=URL
So you can write a bookmarklet that ‘does the right thing’ if you know the site’s base URL.
Trackback supports a few more parameters in the URL so you can send a summary of the reply, and the name of the site sending the ping.
Over at Hit-or-Miss, they’ve been building their own Trackback server in PHP and MySQL.
