Hey all,
I have a client who says that trackbacks to her Wordpress site are only appearing off-and-on ... meaning, not every link to the blog is appearing as a trackback.

My guess is that the sites linking are not adding her trackback URL in their blog engine, but at least one is running Wordpress (which should pingback automatically).

Besides the other sites not adding the trackback URL, is there any other reason they wouldn't be appearing?