Stefan - 10:02 pm on Jan 11, 2003 (gmt 0)

I just had a good look at mine, (there aren't many). It appears that they're listed in order of:
1/ domain name, in title or text of backward link.
2/ occurences of <title>keywords</title> in the backward link title or text.

For me that puts the Google and Dmoz directories about halfway down the list.