Via Dave Winer, Apple appears to have applied for two RSS-related (but not RSS-specific) patents (Dave has the links). I'm not an expert in reading the legalese of patent applications. But they do appear to be written broadly enough so as to include functionality already found in the syndication world. For starters, Microsoft will probaby have some problems with the patents based on what it's doing with RSS in Internet Explorer 7.
I wondered whether Sun might have some issues with the patent applications since they're not specific to any particular XML syndication technology (eg: RSS) and Sun's director of Web technologies Tim Bray has been active in the standardization efforts on the other syndication tech: ATOM. In response to my inquiry, Tim (who is at eTech this week) told me that hasn't seen the patents yet (and my guess is he probably won't since that could break the seals on his clean room). What he did say however is "Boy, if they try to get in the way of anyone else improving the feed-reading experience, all hell will break out." Saddle up folks. It's time to get some air conditioners.