Put nothing in the subject line. Do not use a signature block. I know from teaching 200 that there are many students in the program who are quite capable of writing an article for this journal. Yet I think that students are often intimidated when they see a call for papers for a professional journal. So please try to encourage people to do this.
People can work in groups if they like and submit joint articles.
Maybe I could even interest you in submitting an idea for an article. The guest editor for this special issue will be Samuel E. Trosow of the Boalt Hall Law Library at the University of California at Berkeley. The past few years have seen great changes in the legal publishing industry and in the manner in which legal information is produced, stored, disseminated and used. While the lower entry costs into electronic publishing might be expected to decrease concentration, the opposite seems to be occurring. Papers addressing these and related issues are sought.