Chris Finke: Until July 1, 2007, the DTDs for RSS 0.9 and 0.91 will be available via my.netscape.com. If you are a software developer, use this time to ensure that your RSS software is capable of displaying RSS feeds even if the DTD is unavailable, or have a backup copy cached locally for your parser to use in the absence of the specified DTD. If you are a content provider, either update your feeds to point to another copy of the DTD, or accept the fact that your feed may not be available through feed readers that don't have a backup plan in the case of a missing DTD.
http://blog.netscape.com/2007/01/16/to-dtd-or-not-to-dtd/
Randy: Let me suggest an alternative to anybody that is producing a DTD dependent RSS feed. Use RSS 2.0 instead. The upgrade is quite simple, sometimes requiring only the deletion of a couple lines of code and upping the version attribute.
