According to several sources, Yahoo’s SVP of U.S. Revenue and Market Development Joanne Bradford (pictured here) is planning on leaving the Internet giant to take a new position as chief revenue officer of online content upstart Demand Media.

The surprise move is sure to have reverberations throughout the online advertising arena, but more so at Yahoo (YHOO), where Bradford’s job encompasses a wide range of key revenue-generating duties.

She has also been tapped as one of the execs to play a key role in the recently approved search and online ad partnership with Microsoft (MSFT).

Yahoo declined to comment. BoomTown has also contacted Demand and is awaiting comment.

Bradford had actually once been a Microsoft exec, serving as VP and chief media officer of MSN Media Network. She had worked at BusinessWeek before that.

Bradford came to Yahoo in the fall of 2008, at the tail end of the tenure of Co-founder Jerry Yang, who stepped in as CEO after the previous CEO Terry Semel departed.

Immediately previous to her job at Yahoo, she had been helming national ad sales at then-trendy Los Angeles-based ad services company Spot Runner.

Demand will be her second time going from a large company to more of a start-up.

But–unlike the troubled Spot Runner where Bradford worked for only six months–Demand has been on a growth tear of late with a social media strategy that is also being pursued by AOL (AOL) and others.

It owns heavily trafficked sites, such as how-to juggernaut eHow and the health- and fitness-focused Livestrong.com, putting Demand in the list of the top 20 Web properties.

It reportedly has about $200 million in annual revenue–mostly from advertising, but also from a domain registration business–and is profitable with several hundred employees.

The Santa Monica, Calif.-based company is headed by serial entrepreneur Richard Rosenblatt (pictured here), former chairman of Intermix Media. Intermix was the parent company of MySpace, which was sold to News Corp. (NWS).

Armed with an astonishing $355 million in funding from a range of prominent investors, he has been trying to fight some mainstream media depictions of his social media content company, especially one report that called Demand a “content mill.”

Via its Demand Studios, the company uses an army of freelancers to produce all kinds of content for its sites and others, using a complex automated system, but which also includes vetting and editing.

In fact, irked at the characterization of Demand as a content spammer, Rosenblatt even issued a manifesto for Demand in January.

“There has been so much misinformation about our model and what we actually do, that I thought it was a good idea for our company and those who work for us to lay out our principles,” said Rosenblatt in an interview with me at the time. “We are so different from traditional journalism, which I have nothing but admiration for, so it was time to make people understand that.”

The role of Demand Media, said Rosenblatt, was to help readers solve problems, laugh and get good advice, while figuring out how to create a profitable media business in the digital age.

(Walt Mossberg and I have invited Rosenblatt to share the stage at the eighth D: All Things Digital conference this June, along with former Wall Street Journal editor Paul Steiger, who is trying to save investigative journalism at a nonprofit called ProPublica, to talk about it all.)

If Rosenblatt is successful, Demand appears to be aiming for an IPO or merger with another company. Ironically, Demand has also been eyed by Yahoo in the past, as a possible acquisition.

Nabbing a top Web exec like Bradford from Yahoo is obviously a definite step in raising the stakes for Demand with big, established advertisers.

That’s because Bradford is well-regarded in the industry and is a prominent player. She recently signed a high-profile deal with Hollywood producer Ben Silverman to create premium content for Yahoo.

Bradford’s departure will be seen, both internally and externally, as a definite blow to turnaround efforts by CEO Carol Bartz. Bradford currently reports to Hilary Schneider, EVP of Yahoo’s U.S unit.

My reporting does not indicate that Yahoo’s top brass know about Bradford’s expected move, so it is not clear who would replace her at the Silicon Valley icon, which has been hard hit by an exodus of talent over the last two years.

Internal candidates could include 11-year Yahoo veteran Mitch Spolan, VP of North American sales, or Seth Dallaire, a former Microsoft exec whom Bradford brought to the company last fall as VP of mid-market sales, a newly-created role responsible for all mid-market sales efforts across search and display advertising.

More to come, obviously…

Hence, another round of funding for 5min, a video start-up that just raised a $7.5 million B round. New investor Globespan Capital Partners led the round, and Spark Capital, the VC shop that has made several video bets (along with a big one in Twitter) made a second investment.

5min has now raised $12.5 million since 2007. Co-founder Ran Harnevo won’t discuss valuation, though I’m told it’s up from its A round, which is an accomplishment in and of itself.

“People do understand that video is the next thing. They just don’t see reasonable business models,” Harnevo says. “That’s the next thing that you have to do. You have to go into VCs and say, “I know how to do this.”

The company, which is based in New York City but has its roots in Israel, takes a different tack toward video than the would-be YouTubes: Rather than serving as a portal for user-generated clips or movies and TV shows, it cobbles together a library of how-to videos and distributes them to sites that don’t have any videos of their own. It now claims to reach 14 million video views across 200 sites.

There’s plenty of competition for how-to sites and videos, too, of course. But Harnevo claims that he’s been able to sell all of his inventory so far, and predicts he’ll be profitable in the next 18 months.

He was similarly optimistic six months ago, when he let me try my hand at conducting an interview with a Flip Mino. I never ended up publishing the clip, but now seems like a good time to do so–as long as you’re willing to put up with crummy sound, shaky camerawork and a stretched image. As I said, I was trying this stuff out.

Just about every thing we discussed in this interview still holds up, except that 5min now boasts 100,000 videos, up from 50,000 in December.