All of us who use the mailing list have either come accross the nuisance of top-posting, or have been *scolded* by others on the list for top-posting and other non-compliance of email etiquettes. But I guess it is better we understand/explain WHY we need to follow these guidelines.
I recently read a series of blog posts [0] Aaron Toponce on whats and whys of email etiquettes. Hope it will help everyone understand this issue better.
[0] http://pthree.org/2010/09/18/email-netiquette-part-1/