The conversations inspiring (and inspired by) FDML, a proposed "list of feeds" format, are quite interesting, especially those debates concerning feed auto-discovery. In September Jeremy Zawodny noted two possible auto-discovery methods:
I see two obvious ways that could happen.
The file, like /robots.txt could reside at a well known location with a well known name, say /feeds.opml or /rss.opml? This has the advantage of being very simple.
We add a new, optional <link> tag that tells tools where they can find a relevant OPML file that contains information about the various feeds offered. This has the advantage of being like what we do today and it provides a bit of flexibility.
Tim Bray sufficiently argues against option number one, noting that we shouldn't start grabbing namespaces, especially this early in the Web's development. Joe Gregorio agrees, deriding current namespace hogs robots.txt and favicon.ico. On a related note, Dave Winer considers a "folder for metadata" on the grounds that reserving one name (for one folder per site) is a small cost with lots of benefits. We'd agree if we had any reason to believe future generations won't find an excuse (like Dave has) to steal more names. Reserving namespaces should be avoided as a matter of principle.