Joshua picks up on the trackback conversation, but there are many problems with the comparisons of trackbacks and referrer tracking (I am posting this for clarity not to poke at my friend Joshua and comments are not turned on for his entry or I would post there). It sounds like referrer logs are not set properly in what Joshua is using for a comparison to trackback. It may be that Movable Type is not set to take full advantage of referrers, which is sad. Joshua and the posts he links to explain trackbacks properly.
Of the three comparisons of trackbacks to referrer only one is correct, trackbacks do not require an actual hyperlink to the article to work properly (why one would not have a link to what they are discussing is odd as it is the Web). The other two comments are not correct if referrer logs are setup properly. In my last 100 referrers page I can see exactly what page a link came from (I used Charles Johnson's referrer as a base for mine). If the hyperlink is clicked from a permalink page I can see the exact page the link came from and if it links to my permalinked entry I can have categorical sorting also.
I have not seen a need for trackback on my site my referrer log (real-time) and access log show me exactly what is going on. Oddly there is always a lot of talk about trackback on blogs, but very rarely are they ever used. This may point to a usability problem with trackback. Referrer and access logs on the other hand do not need this extra step for the site owner to get the information.
Once I get unburried with paper work for work and have a clear head that the completion will bring I may implement a referrer version of trackback for public consumption, unless the lazy web does it first.