This happened a few minutes ago:

And I cannot find the relevant post. Tried to reproduce by upvoting someone else, without luck.
Posted 04 February 2013 - 12:40 AM
This happens when you get an upvote in the developer journal section. You get the upvote here ![]()
Posted 04 February 2013 - 01:09 AM
I was gonna suggest phantom possibly voted you up, just because that would seem appropriate, given his name and the blank log entry...