Former Facebook exec Owen Van Natta will take the CEO job at a music discovery site called Playlist, a move that had been speculated last week, after he did not end up taking another position as head of MySpace Music.

Van Natta’s arrival at Playlist was not the only news for the Palo Alto, Calif.-based start-up–former AOL exec Bob Pittman’s Pilot Investment Group is also investing an undisclosed amount of money in Playlist. Pittman will also join its board.

Playlist has previously raised several million dollars, said sources, but the new funding is many times that, to total about $18 to $20 million.

The move to Playlist is an interesting one for Van Natta, who has looked at a number of jobs since leaving the high-profile social-networking site earlier this year.

He has talked to a wide range of companies, sources said, including Microsoft (MSFT) and a range of start-ups, as well as with MySpace, which is owned by News Corp. (NWS). (News Corp. also owns this site).

Those talks between Van Natta and MySpace to run its new music initiative did not pan out for a variety of reasons.

But he has long expressed a desire to become a CEO of a company, rather than just head to another executive job within a larger company, so the move to run a start-up is not a surprise.

In an interview this afternoon, Van Natta told me he got very intrigued by the possibilities at Project Playlist, which was the first iteration of the start-up and in which he is an investor, due to its viral growth.

And, indeed, Playlist has grown quickly to become one of the larger music communities on the Web, claiming that more than 38 million music fans monthly, sharing playlists via its Web site and also widely distributed embeddable widgets. The site has tens of millions of daily page views, according to surveys.

To get to those big-scale numbers, Playlist essentially has offered users a giant linking service for music, not unlike Google (GOOG) with all information, pointing users to promotional, free and sometimes illegal music and music video tracks all over the Web.

Those links to illegal music have resulted in a lawsuit aimed at Playlist from the music industry, sources said, a sadly typical experience of many online music services.

The usual tactic for the music giants: Sue first and shake down later.

Under Van Natta, I would guess, Playlist is likely to reach out to music companies and strike deals.

The company also needs to settle on its main business plan, which appears to me to have been less important than its explosive growth.

Playlist currently does have some small amount of advertising on the site, and seems to be making most of its scratch from sending leads to ringtone sellers.

Van Natta did not want to reveal specific strategies for Playlist going forward, only noting the opportunity is large.

“Discovery around music is exploding on the Internet,” said Van Natta. “And the company that does the best job of taking advantage of that is really going to be huge.”

That said, there have been a lot of music-aimed efforts like Playlist in the music space, with a lot of different business plans and varying degrees of success, ranging from the Apple (AAPL) behemoth iTunes site, which sells single songs, to the CBS (CBS) music service, Last.fm, which relies more on advertising revenues.

Other contenders in the space include the Rhapsody subscription service from RealNetworks (RNWK), music discovery service iLike and many others. MySpace has also waded deeply into the music space, and Facebook is also reportedly weighing its own service.

Van Natta was one of Facebook’s earliest and most prominent execs, serving in jobs like COO and also Chief Revenue Officer while there.

He came to Facebook in the fall of 2005, after a stint as VP of Worldwide Business and Corporate Development at Amazon, and was part of the founding team of A9, the Amazon search company.

“I am excited to be building a company again,” said Van Natta, who has taken many months off since he left Facebook in February.

But–as many readers have requested–they will all be available in their entirety over the next weeks in this column.

Here’s Part 3 of 4 of an interview Walt Mossberg did with the Gates Foundation’s Melinda Gates.

(I will be posting one video part of the discussion with Melinda Gates every day this week through Thursday.)

As you will see, Melinda Gates is articulate in ways that are critical to the task that she and her husband–that would be Microsoft (MSFT) Founder Bill Gates–have put before themselves: Big league philanthropy with deeply effective results, specifically in health and learning.

In this video, Melinda Gates talks about the best ways to fix the broken parts of the public high school educational system in the U.S.

While BoomTown does not usually do funding announcements, the $7 million that the adults-only social network Zivity will be announcing today is interesting for one reason.

No, not the fact that it builds its business model on the back–well, back ends, to be more precise–of photos of women in various stages of undress.

Get your minds out of the the gutter!

It’s because it is one of the few Web 2.0 companies that is trying out a subscription business model, as opposed to every other online company these days, all of which are chasing ad-supported nirvana.

Today, the San Francisco-based Zivity is nabbing that $7 million from BlueRun Ventures and Founders Fund, both of which have backed social-networking widget phenoms like Slide.

In fact, Zivity co-founder Scott Banister is on the board of Slide and was one of its earliest investors. (Banister, whose wife, Cyan, is also a founder and model on the site, has also been involved with a wide range of start-ups, from Overture to PayPal to IronPort.)

So instead of, say, Viagra banner ads, Zivity users pay $10 a month to look at the “tasteful” naked ladies pictures uploaded by users. The company must approve of the professional-quality photos, using a series of guidelines (no sex acts or close-ups, for example).

“Look, Lindsay Lohan just did a whole photo session similar to what we have on our site, so what’s wrong with 3 million other women wanting to do it,” joked Banister in an interview last night, referring to the recent series of pictures the troubled actress did a la Marilyn Monroe for New York magazine. “We are creating a place where the more controversial material can be published online without worrying whether advertisers are willing to underwrite it.”

Well, we will not get into a debate as to why we probably should not be playing copycat with the train wreck that is Lohan. But Banister does have a point about the need for different kinds of business models that don’t rely on advertising.

In fact, Zivity–which was seeded in 2007 with $1 million in funding–pays contributors who are more popular in a revenue-sharing plan via voting. Right now, for example, the most popular “photo sets” includes images of Cupcakes, Pearl and Damanda (pictured here).

There is also an increasing element of social networking, among the models, photographers and others, which does mimic more straight-laced sites.

In the press release for the funding, Banister compares Zivity to the popular cable channel HBO. “We think of Zivity as the HBO of the Internet,” he said. “Unlike free social networks and other user-generated content platforms underwritten by advertisers, our subscription-based business model offers us real freedom–to publish uncensored content and to pay our content producers generously.”

While the site is only comparable to HBO if it ran only “Taxicab Confessions” and “Real Sex” in an endless loop and you had never heard of “The Sopranos” and “Entourage,” its sure-fire subscription base might allow Zivity to be one of the few Web 2.0 companies that survives the coming washout.

But before you fire up that browser, the site has only 10,000 beta users now, with another 30,000 on its wait list. While you can sign up to get an invite or be invited, the open public launch is not until 2009.