I am on the list, and when I log into Fastlane, it asks me to accept/decline as well. I can also view my award letter, which is dated March 31. So this seems real.
I heard from many people that broader impacts is extremely important. I worked a lot on my essay this year. However, this is the third time I applied, and last year my essay received almost perfect marks (top scores on all but one criteria by one reviewer, who gave the next-to-top), but I only got honorable mention. The same happened to a friend.
For whomever this is useful for: I have 1 refereed publication, 6-8 conference posters, one conference paper, an NSF honorable mention, a conference travel grant, and 4-5 years of research experience. Also near-perfect GREs, but not so hot grades (3.5). But, as I said, I think broader impacts is pretty important.