Hulu may insist that it's not a YouTube-killer, but the joint venture between News Corp. and NBC Universal is certainly making a name for itself in the online video market.

Traffic to Hulu and its partners has already surpassed traffic to all U.S. television network websites, including those of its owners, the company said, and Hulu is adding more affiliates to a list that already includes AOL, Yahoo and MySpace.

TVGuide.com, Break.com, BuddyTV.com, Flixster.com, MyYearbook.com and Zap2it.com will join as partners, and TV.com will now feature both video content and video advertising from Hulu.

"While it is extremely early in terms of Hulu's history of serving users, we're quite excited to see such positive trends in Hulu's growth and viewership," Hulu chief Jason Kilar said in an interview with Reuters.

Hulu offers full-length streaming episodes of Fox and NBC programs like "Family Guy" and "Saturday Night Live" and feature films interrupted by commercials. More than 63 million videos have been streamed on Hulu, and users are watching more than two hours of content a month, the company said. That still pales in comparison to YouTube, where viewers watched 4 billion videos in April.

Despite being branded as a YouTube-killer upon its launch, Hulu has shunned the title and has even partnered with YouTube to gain viewers.