It's a little known artifact of the Steem blockchain protocol that any payout less than $0.03 doesn't actually get paid out. So, if you gave an upvote worth $0.01 (as I often used to do for comments that weren't particularly valuable, but that I thought deserved acknowledgment of some sort), and no one else gave an upvote to bring the total to over $0.03, they actually wouldn't get ANYTHING from that. Which I think is a dumb rule, and not well-advertised.