I replaced the initial offsite link to SFWA's Nebula Ballot with an onsite news page listing the nominees (with a couple spelling corrections), along with statistics about past nominations and wins. If obsessive attention to statistics is good enough for Oscar prognosticators, it's good enough for us Nebula and Hugo watchers.
It's remarkable that 5 of last year's 7 winners (counting people, not categories) are nominated again this year. There are 16 first-time nominees this year, though that counts 9 from the script category--the others are Moon, Baker, Doctorow, Vukcevich, Brockmeier, Van Pelt, and Gloss.
None of the novelette nominees has won before.
Of nominees who've never won before, Jack McDevitt and Karen Joy Fowler lead in nominations, with 8 and 7 prior nominations respectively.