Key server question

[Lars Hecking]

 I installed GPG a few months ago and created a test key, mainly to
 play around with.

 To my big surprise, I discovered today that this key is now on the
 key servers! How did it get there?

 Does the keyserver directive in ~/.gnupg/options go both ways, or should
 I assume that one of the individuals I made my key available to under
 the condition not to publicise it did just that? Maybe accidentally?

 There is no harm in my key being there, I'm just wondering how it
 got there.