Programmer gets del.irio.us about del.icio.us

Last week's debut of del.irio.us, which is essentially an open source knock-off of the social bookmarking site, del.icio.us, did not go over lightly for many partial to the incumbent's folksonomy/tagging service. Stephen O'Grady, a RedMonk analyst (and a del.icio.us user), points to a thread on the del.icio.us mailing list where Steve Mallet, the programmer behind del.irio.us, is under attack. O'Grady pinpoints several issues that the clone raises, such as questioning how long will open source development remain a competitive differentiator, and the potential for the newcomer to fracture the tagging community. The bottom line:

All in all, I think this example highlights the fact that there are right and wrong ways to clone applications or services; or maybe that's wrong - there are righter and wronger ways if not an absolute black/white determination. I think the degree to which del.irio.us flatly copied much of the del.icio.us design is not entirely appropriate, but at least in the short term I don't expect it to make much difference.

What do you think? Could have Steve Mallet created a similar service without much copying, or is the del.icio.us UI the optimal de facto standard?