I put up the Web 2.0 Validator site: web2.0validator.com (now on vacation until I get around to updating some code).
Interestingly, someone wrote to me asking how I managed to get such a domain; I pointed out the domain is simply 0validator.com, nothing magical.
Which of, course, means I can plan on web3.0validator.com :)
See the reasoning behind the switch from del.icio.us to Delicious.com:
So why did we switch to delicious.com? We’ve seen a zillion different confusions and misspellings of “del.icio.us” over the years (for example, “de.licio.us”, “del.icio.us.com”, and “del.licio.us”), so moving to delicious.com will make it easier for people to find the site and share it with their friends.
I always liked the hack (I still us it; it's shorter), but I'm obviously not an average user. You are completely right that being "clever" in your domain (or really anything regarding your product) is often not a great plan.
Remember that nobody had really done domain names like that (maybe cr.yp.to? i also have had burri.to for 15 years...) in a big way before, so it wasn't clear that it was a bad idea at the time.
Some of the other domains, like http://delicio.us/ worked correctly too. I wonder if Yahoo! kept them all.
If I was starting over, I'd pick something else.
// I'm still jealous of Matt Mullenweg's personal domain though: ma.tt is a pretty awesome domain hack.