Hi Sue, there are two aspects to this and dust is technically not the $0.02 talked about here.

The concept of dust votes was introduced to avoid users spamming a huge amount of small votes. A dust vote is equal to a 100% vote of a 1 SP account. As the Steemit interface isn't allowing you to change the voting bar until you have 500SP in your account, this should rarely happen for normal accounts. A dust vote will throw an error, so it won't add up with other votes.

In addition to this, there is a Minimum payout threshold, which is set to $0.02. This is something impacting many users as upvote values of $0.01 etc, will be changed to $0.0 on payout day. This is often referred to as Dust, but technically it is not... ;)

The dust threshold will be changed in HF20, but I have seen nothing about the minimum payout threshold.