Counterpoint: "xkcd"
Given its target audience, it works for xkcd. Geeks like geeky sounding, hard to pronounce names (like gnustep, xmlhttprequest and PostgreSQL). If a name like 'xkcd' were chosen for a consumer service, it probably wouldn't work very well.
I named my company in the same way Mr. Munroe named his webcomic: a four-letter domain available in .com, .net, and .org.
"Actually the domain name came after the instant messaging screen name, which I picked late one night. Five, six, maybe seven years ago, I was tired of having names that meant something. Skywalker4, Animorph7... I wanted to pick a name that I wouldn’t get tired of. That would just always mean me. So I just went down combinations of letters that weren’t taken, until I could find one that didn’t have any meaning, didn’t have any pronunciation, and didn’t seem like an obvious acronym for anything."