Well I'm a bit beyond my deapth here, but here goes anyway. How about
a combination of a <a href="foo?action=subscribe&feed=bar">common
button</a> and a user preference selection at a web site. Then foo is
the URI of a script that interacts with a user preference for a specific
local or golbal resource. The script page would display a simple
selection of known aggregators and the user simply selects the radio
button and the resultant post is to the local or global resource. The
foo could be common to all blogs, so that the user's preference for foo
could be kept in their cookie and a user would need to select it only
once. Whould that work?
What if they don't know about my aggregator, or one that's run behind a
firewall?
It can certainly be done using cookies and a centralized registry,