I am sure there are layoffs going but they are small so it doesn't meet the bar where there has to be a email from the top. Also I am sure who ever posted the layoffs for the 5th and now the 13th will post a new one for the 20th. So take these with a large grain of salt.
I've noticed that sometimes companies do layoffs in small increments, to avoid both media attention and disruption in the office. Not saying this is what NetApp is doing, but it is a possibility.