No blog post, no -- but you can link to my HN comment[1]. Also, as long as I'm commenting again on this, I should point out that pkill also had an Easter egg of sorts: "pkill -V" was a shorthand for killing everyone's least favorite Solaris daemon: vold. (This option was ripped out when vold itself was ripped out in 2006.)

[1] http://news.ycombinator.com/item?id=4306515