Re: Not puff piece. Not employer
Many publications have an editorial policy that where an author has (or has had) an interest that might potentially influence the perspective of their article, they are required to note this in the article footer.
If Matt Asay has recently worked for MongoDB then that should have been noted. (I am not suggesting that that necessarily skews his opinion (after all, he is apparently no longer working there), but I do think this should have been noted, so that readers can decide whether or not that might reflect any slight bias in the article (again, I am emphatically not suggesting this, but being open and transparent about these things is better).)