All of the XML content is accessed via the ".xml" action... To get RSS or RSS2 out of that (not viewable in most browsers), add ";type=rss" or ";type=rss2" to that URL.
The default feed is the 5 most recent posts:
http://www.simplemachines.org/commun...hp?action=.xml
There are several "sub-actions" available to this action, specifying exactly what to display:
Recent Posts (displays the most recent posts that you can see)
"Sub-action": recent
Default: Shows 5 most recent posts
Available options:
limit=x - display the "x" most recent posts (if number is less than 5, it will display 5. If number is larger than 255, it will display 255).
board=y - display only the recent posts from board "y"
Example:
http://www.simplemachines.org/commun...rd=72;limit=10
News (displays the first post from the most recent topics that you can see)
"Sub-action": news
Available options:
limit=x - display only "x" items
board=y - display only news topics from board "y"
Example:
http://www.simplemachines.org/commun...rd=72;limit=10
Members (displays most recent members) - note: There is a bug in the current version of SMF that prevents this from working right - see Latest Members XML Problem for the fix
"Sub-action": members
Available options:
limit=x - display only the "x" most recent members
Example:
http://www.simplemachines.org/commun...mbers;limit=10
Profile (displays the "profile summary" data in a nice XML feed for the specified user)
"Sub-action": profile
Required option:
u=x - display the profile info for user whose ID is "x"
Example:
http://www.simplemachines.org/commun...=profile;u=150
Now - you're probably wondering what you can do with this. Quite a bit actually.
You can syndicate this stuff by giving people these URLs to use on their sites (they will need to have their own RSS parser to deal with it though - CaRP is a good free one (requires PHP)). You can also use PHP's XML Parser Functions to format the output the way you want it (although you can also do this using SSI.php).
You can also subscribe to these feeds through an XML reader, Firefox, Thunderbird or any other software that supports XML or RSS feeds (note - Outlook and Outlook Express do not support this...) - you will need to have either "type=rss" or "type=rss2" somewhere in the URL for it to work. If you would like to know how to set this up in Firefox or Thunderbird, let me know. Enjoy!