Slightly embarassing, but I think that the Times is confusing "Unique Visitors" (how many unique cookies are counted by a site - a reasonable proxy for people visiting the site) with "Unique Viewers" (a syndicated video player concept - how many unique cookies were counted by the syndicated player; a reasonable proxy for the number of viewers who were served video by the site).
In layman's terms, the first number would represent, in our example, the number of people who visited Hulu.com (unique visitors), while the second (unique viewers) would represent how many people watched a Hulu sourced video, whether on Hulu, a third party site (like Fancast), or embedded elsewhere (like on somebody's blog).
A visit to alexa or compete shows the number of "unique visitors" to be comparable to what Nielsen reported (a fact others have noted). And guess what? Even Comscore doesn't put Hulu in the top 50 for April 2009 - which means even Comscore suggests that the number of unique visistors to Hulu is less than 19M (if someone has the actual number, I'd appreciate it).
So... move along... nothing to see here...