If your movable type blog gets hit excessively by trackback spammers, you may find yourself unable leave trackbacks for yourself due to a "403 Throttled" error. This http response is from movable type in an effort to slow down mass trackback ping spammers. I will go over some quick fixes, some longer term fixes and some very technical info for those intending to modify their installation of MT to handle trackback ping spam better. This article will apply to MT3 and MT4.

Last week, Six Apart announced the release of Movable Type 4. MT4 is a major upgrade in that it adds many new features and supports a more robust templating system. This site is run by MT4 and has been upgraded from version 3.35 to use the new templates and features. (Edit - 2-25-2009 - this site is now running drupal 6.9) Upgrading the underlying system is fairly straight-forward, but getting all of your customizations moved into the new templates is very work intensive and requires a lot of research. I'll go over what I learned and did to successfully upgrade this site and hopefully save you some time.