Here's a list of sites for drupal developers to play around with.

HTML Comments without moderation

• www.themallblog.com
• www.eatsleepandcode.com
• www.layt.net

Anonymous node editing

• mature-ip.eu/node/115/edit
• drupal.kldp.net (Its all Korean I dont know what all is possible)
• drupal.x73.ch
• proves2.iws.es/drupal
• emusic.mozdev.org/drupal
• www.news7newslinc.net
• futuregrid.org
• www.aidsvancouver.org
• jennycrumiller.com

So you came from the The MALL blog, this is because of opened out HTML comments on the MALL blog.
The MALL blog has full html support in its comments, which is a dangerous feature.

More sites :

• www.eatsleepandcode.com
• www.layt.net
• mature-ip.eu : Any nodes can be edited on this site, wierd!!! Fix it ASAP