Sounds like the Nebulas have revised their rules and the changes should help the Nebulas make sense.
The one that makes the most sense to me is, and this is Niall's wording because apparently I can't read rules and figure out what it means (seriously, not being sarcastic)
No more rolling eligibility; the awards are now tied to the calendar year
Now, what I hope this means is that the Nebulas in 2010 will be for the stories published in 2009. I almost called it the 2010 Nebulas, but I think technically that it would be the 2009 Nebulas. I just have problems calling awards which take place in one year by the naming convention of the previous year.
That just sounds stupid, but it's my issue.
Regardless, I believe that this particular change will be a good one.