If you are developing WebDAV client or server software get WebDAV Next Generation Collaborative Web Authoring by Lisa Dusseault. [put link to Amazon and review that I will write in bookshelf]
Future link to oacs-dav OpenACS WebDAV Support package
Future link to tDAV AOLserver WebDAV module
This section will list the little quirks that you might find testing with various clients.
MS Web Folders
MS WebDAV clients are very picky that your XML be perfect and the date formats must be exactly what the client expects. [put more detail here on the formats]
MS Word
Word is super picky. (test with relative URLs in propfind) The href property in PROPFIND must match exactly the URL it thinks it should be. So if the web folder is mounted as http://foo.example.com the propfind href property better be http://foo.example.com and not just http://example.com. To make sure it returns what you think it is, set the SystemURL parameter of ACS Kernel in OpenACS.
I think the same thing happens on Windows 2000. I think Windows XP and Word 2003 do not always have the same problem. More testing is required.
No other client I have found cares about that.
Mac OS X
This is fixed! Jeff Davis did some great debugging, and we can workaround the problem. It is fairly complex. ns_returnfile doesn't send headers when a file content length is 0. It is worked around in OpenACS to return the proper headers. --get more from email exchange with jeff--
Aside: Oracle 8i doesn't support timestamp with timezone datatype, or fractional second precision in timestamps. In OpenACS dates in Oracle are stored without timestamps, in Postgresql they are stored with a timestamp.