Hulu, the online site that offers shows from NBC, Fox, and ABC -- and is owned by the corporate parents of those networks -- may have attracted a sizable number of viewers after its launch two years ago, but that number has failed to expand significantly in recent months, according to Nielsen Research, and neither has Hulu's revenue. It's estimated that the website earns less than $100 million a year -- split three ways -- a piddling amount for the networks, who are used to earning around $1 million from advertising on a single half-hour TV show. Moreover, some analysts have expressed concern that Hulu may be cannibalizing the shows' broadcast audience. And reports have even indicated that some viewers are canceling their cable subscriptions and watching their favorite shows via Hulu and other video websites instead. Now, according to today's (Thursday) Los Angeles Times , Hulu is planning a premium subscription service called Hulu Plus that would still allow viewers to watch episodes of some recent shows but also "a more comprehensive selection." According to the newspaper, which cited people with knowledge of the plans, the premium service would cost $9.95 per month.