Concern has arisen in the last month over the trend toward creation of new URI schemes for use as namespace identifiers in new XML applications.

Writing on the W3C's URI list, Tim Berners-Lee expressed surprise at WebDAV's use of the DAV: scheme:

The DAV spec really invents a totally new whole URI scheme just for a namespace? If there has to be a root of anything anywhere, then with whom will it be safe? The root of the URI space now become a free for all...

Earlier in the month, Dan Connolly had commented on the SyncML spec's use of the syncml: URI scheme.

I wonder why they used a new URI scheme for their XML namespace; what's wrong with http://syncml.org/2000/metinf ?

While inventing new URI schemes for namespace purposes certainly seems gratuitous, it is worth some investigation as to why this is happening--it may be that http: URIs for namespaces still cause discomfort and confusion, causing some to opt for a custom solution.