I have had some ideas regarding more community sharing of news feed resources. How can aggregator developers better publish their users subscriptions and activities? Would the end user be willing to have their data published? Share Your OPML is a start. What if aggregators had Share Your OPML functionality built-in? Locally stored and placed online as well. Most users have some online space available, either through their ISP, personal site, MSN, .Mac, etc.
You have the dateModified field defined in the head. Expand the outline element to include a dateModified for the element. There is then a distributed format available to determine who has the latest goods. A trusted server would then need to connect the ownerName and ownerEmail to its client machine and aggregator, check for availability, and serve the location of the seed.
Too complex? Other ideas?