Something similar to the iCal standard which Apple’s iCal, Mozilla’s Sunbird, and PHP iCalendar. Syncronization wouldn’t require any special server-side work, just a central repository to store a sync file. This could be via ftp, sftp, scp, webdav (and therefore .Mac), or local file (say to put on a USB key).

The sync file would be a digital bookmark/highlighter for all of my RSS feeds.

Ross here…Brent Simmons is working on sync for the next version of NetNewsWire. The company that recently bought him out also operates a decent web-based newsreader and of course they sell an aggregator for Windows. Presumably, the idea is that you’ll be able to sync your feeds with their central servers and then read news in NNW, in their web reader, etc. I think it’s logical to assume this is a paid-only feature.

All that said, the answer to your direct question would be “no” (at least as far as I know). I see a definite incentive problem standing in the way of creating such a standard: at this point the parties that would make use of such software would want to lock you in to their reader(s).

As I see it, some organization (rather than the individual end user) would have to pay for and operate the server infrastructure that would bring this software to life, and we cannot expect them to do so out of the goodness of their hearts. If anyone would do something like this I’d say Google would be the most likely, but even they have their own web-based reader.