I didn't want a .com because I don't think I have anything commercial to offer on my personal web page. My criteria were fairly simple -- easy to type, relatively easy to say, and unlikely to offend others in English or other languages.

Having most net neighbors with a Levenshtein distance less than 2 be non-offensive web sites was also a plus so that visitors don't get a bad experience with a typo. My guess is that will also cut down a bit on spam from accidental or purposeful misspellings when people sign up for things like a free nytimes.com subscription.

The non-changing URL and email address is really nice, as is the ability to do things like give out different email addresses to different organizations. Many times I'll want to receive all of the email from some place, but don't feel like getting locked into receiving spam from their affiliates. In those cases, I'll give out an email address like peter+yahoo@diff.net; if the spam gets annoying enough I just put it in a killfile.

The only really annoying thing about diff.net is that it is aurally ambiguous; if you say that your email address is "something at diff dot net" it's not obvious how many 'f's there are.

At least diff.net isn't like "Dave-O" (davo.cc. :)