Defining OPML and relating to DITA maps

From an information design perspective, OPML is a great format for outlining information, showing information's hierarchical structure and relationship to other entries. I had only really thought about OPML applications as advanced organizers for lists of RSS feeds, but I suppose there might be other applications as well. This definition on whatis.com alludes to multiple organizational uses for OMPL, saying "...OPML has been used to organize many kinds of data as it may be customized for each application." But what are these other uses for OPML? Can anyone point me to examples?

I sometimes find it difficult to articulate my enthusiasm for OPML, and this definition offers a great overview. I always have seen OPML as a great way to store lists of RSS feeds in logically-named folders. Here's another excerpt from the definition:

OPML allows a user to classify where content should be placed within a hierarchy as it is being created. This feature makes the format extremely useful for the creation of "living documents," where relationships and content are continuously updated.

I think that OPML and DITA maps may be closely related cousins in the list family. From the DITA specificiation, DITA maps organize topics for output to a specific deliverable, including generating navigation files and links to related topics. DITA maps offer the ability for quick re-organization of topics to create multiple deliverables. I envision DITA maps as offering an alternative to single-sourcing by letting you pick and choose from a large array of topics, whittling the DITA map down to just the print book combination or just the online help combination that you want. With the power of DITA maps, you can create two subsets of documentation from the same superset of topics. I think that the "living document" description for OPML is also fitting for DITA maps. Just ask Jen Linton, who co-authored the Introduction to DITA: A User Guide to the Darwin Information Typing Architecture book using DITA. She was able to completely re-organize the book within weeks of publishing by simply changing the DITA map. Nice! Now we just need a drag-and-drop interface for editing DITA maps.

If you'd like to work with an OPML editor, there's one you can download on the opml.org site. And remember that there's a TalkBMC OPML file available for downloading that contains an organized list of all the blogger feeds, comment feeds, and podcast feeds for talk.bmc.com. Very handy!