We've been saying for some time now that the first step toward increasing the turnout on the Hugo Awards is to get the people who are already eligible to vote. This year may have seen a small step in that direction. We could still do much better. There are more than 5000 people eligible to vote, so while 864 is good, there's a ways to go, and we'll keep it up.
I hope that this year's live Hugo Announcement Ceremony is something that future Worldcons decide to repeat, including cooperating with line online coverage so that fans from around the world can participate in the excitement.