The Moodle forums gave time for posts to be composed with care, and even edited after posting.  I'm happy that my Moodle posts generally gave a fair representation of my thoughts at the time of writing.  SL didn't do that.  Also, SL didn't provide an opportunity for anyone to hold the floor, to request attention from all the others to what was being said by the one participant, as would be the case in a real seminar.  Maybe a 'conch' icon or an appointed chair person would address this problem.