A lot of forums do not allow non-members to view threads and posts without already being a member. Since registration is quick and easy, people can just register if they just want to read the forum. The reason this would be very very helpful is it will keep web engine crawlers from getting into our forum and putting it into their search results. A simple google search of "chemlex" reveals all my posts. If you wanted to change this, it would increase privacy and it would encourage more people to sign up instead of lurking about namelessly.