I've finally implemented replying (this involved learning about regular expressions, which are very useful when searching and substiting strings with somewhat complex patterns), and the main thread view displays the newest messages on top. As far as I can tell, the message board is feature complete (that is, you can browse, create and reply to posts). Now I can either move on to a different project (I'm thinking of doing either a web album thing where users can upload images, write commens and put them into collections, and browse the collections of others, or perhaps an e-card service) or further refining the message board (by adding searching, cookies to remember the user name, displaying only messages that are new since the last visit, etc.). Either way, I'll be further using and learning Perl, which is really the whole point.