Where I work we use phpBB and I was surprised to see version 3 didn’t have built in RSS support. I found a mod, but it contained several files and required modifying several more files. I put together a hack that will pull the latest posts that are approved and non-reported; However, it will keep them unique to a topic. So if the last 5 posts are for a topic called “That is awesome”, it will only show a link to the last post on that topic and will look for the other latest posts from other topics.
It’s configurable with a item_limit (number of posts to pull) and word_limit (how long the description is). However the description is just the title for the last post, so it will most often be “RE: original post title” unless the user changes it when posting. I could of done another query in a loop to the table phpbb_posts and pulled out the corresponding post_text, but didn’t want to have the overhead. Although you could easily modify that in and cache the file for say 5 or 15 minutes. Think of this as a head start to get the feeds from your forum for whatever you plan to do with them. 😉