Americans are watching more streaming online video than ever and the big winner continues to be Google-owned YouTube.

The comScore Video Metrix report for July 2007 — which looked at the usage of streaming video sites only — reveals that nearly 75 percent of U.S. Internet users watched videos online, up from 71.4 percent in March, and the average viewing time per-month was just under three hours.

Google-owned video sites (which basically means YouTube) lead in terms of unique viewers, grabbing 37.6% of the market (67.8 million), with Fox Interactive in second place with 19.9% (35.8 million) and Yahoo! Sites a close third with 19.6% (35.3 million).

While it’s yet-to-be confirmed, TechCrunch reports that News Corp. and NBC’s joint venture, Hulu, has made its first acquisition: Bejing-based startup Mojiti. It’s thought that Mojiti, an online video platform that enables users to annotate videos at specific time points (while also forming the basis for search functionality) will provide a part of the technology used to power Hulu. Mojiti founder, Eric Feng, was previously at Microsoft Research Asia.

TechCrunch editor, Mike Arrington, expresses surprise that Hulu would go outside for some of its core technology, while conceding that, having missed their previously announced launch date of summer 2007, an acquisition could get things back on track.

Veoh, the company behind the video sharing site of the same name, as well as the Internet TV app, VoehTV (see our review), have announced a new set of funders. Joining ex-Disney CEO, Michael Eisner, along with Shelter Capital Partners, Spark Capital, and Time Warner Investments, Veoh’s backers now also include former Viacom and MTV Networks CEO Tom Freston’s Firefly3 and Jonathan Dolgen, former Chairman and Chief Executive Officer of Viacom Entertainment Group.

That’s a pretty heavyweight media lineup, with plenty of Hollowood/TV network connections, which, moving forward, is likely to be a prerequisite for companies in the Internet TV space whose success will in part be based on their ability to secure major content deals. In this respect, VeohTV competitor, Joost, looks particularly well placed with backing from CBS and Viacom.

The Sunday Times reports that Microsoft has been in talks with the BBC along with “several other European media companies” as it gears up for the European launch of its XBox Live Video Marketplace.

Ross Honey, senior director for media at Microsoft’s content and partner strategy group, is quoted describing the BBC as a “great content provider” and says that Microsoft is “working diligently on multiple fronts to make it happen.” The BBC’s growing library of high-definition content, such as the award-winning Planet Earth series, makes it a good fit for the XBox 360’s HD video capabilities.