The borderline between short story and novelette is very thin. There are a lot of short novelettes out there. In general, certainly when at SCIFI.COM I found myself publishing more novelettes than short stories.

If anything (and this seems to be borne out) --it's usually harder to get enough novellas on a ballot than short stories and novelettes. Because they're too long to read in one sitting and not long enough to totally immerse oneself in? (I don't have answers, just questions)