The vote dust threshold was added last summer as a countermeasure to automated spam of extremely small votes. While it served an important purpose at the time, the feature interferes with the ability for new Steem users to participate in the community and build a following. The dust votes did not impact rewards significantly, but were taking up valuable space in the blockchain. The true issue was in the bandwidth algorithm, which has been updated to prevent this attack. Because accounts will now be created with 0 SP, their initial votes will not be worth anything. Removing this threshold will allow those accounts to interact with others on the blockchain while they establish themselves in our community.

Read The Official Post https://steemit.com/steemit/@steemitblog/proposing-hardfork-0-20-0-velocity