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.

Since I posted an interview with Social Gaming Network’s Shervin Pishevar today on the announcement of his $15 million funding, it seems only sporting to post this lively video interview I also did with his main competitor, Mark Pincus of Zynga, recently too.

Zynga, named after Pincus’s dog, is one of the two main social-gaming networks that are competing for audience by offering highly interactive games of all kinds. Its aim is to be more engaging and create a series of addictive games that users will return to again and again.

Pincus, who also founded the Tribe social-networking site, is a longtime entrepreneur. I met him way back when as a reporter at the Washington Post when he and Sunil Paul launched one of the few start-ups–Freeloader–in the D.C. area.

And I can report that Pincus is as jumpy and energetic today as he was 15 years ago.

He has certainly been busy lining up a spate of fancy investors, garnering $10 million in funding in January, including from: Union Square Ventures, Foundry Group, Avalon Ventures, Pilot Group, along with personal investments from Silicon Valley players Reid Hoffman and Peter Thiel.

Zynga, which is larger than rival SGN, claims 2.3 million total daily active users across Facebook, with its Texas Hold’em game being the largest it offers. Other games include Sea Wars, Blackjack, Attack! and Scramble.

As I said in my SGN post, while BoomTown often makes fun of viral apps, most of which are faddish and juvenile, the better-made gaming apps actually are likely to be a real business over time, as long they remain engaging and fun to play as the classic real-life games are.

Zynga plans on making money through ads, including creating its own ad network for other gamers, as well as via the sale of virtual goods and premium offerings.

Here’s a chat with Pincus at Zynga’s offices (Pincus owns the building, by the way, which also houses a bunch of other Web 2.0 start-ups) in San Francisco:

Today, in yet another episode of the Web 2.0 lottery, Social Gaming Network grabbed $15 million in funding for its widgety gaming apps that are popular on Facebook and other social-networking sites.

The round, led by Greylock Partners, Founders Fund, Columbia Capital and Novak Biddle Venture Partners, will go toward expanding its offerings, which include the popular Warbook, and also its network for other developers to create and publish online games on.

SGN grew out of Webs.com, which used to be known as Freewebs.

While BoomTown often makes fun of viral apps, most of which are faddish and juvenile, the better made gaming apps actually are likely to be a real business over time, as long they remain engaging and fun to play as the classic real-life games are.

After all, who ever gets sick of Candyland?

SGN’s games are not quite that, focusing more on strategy and bang-bang that 12-year-old boys of any age so love, but, CEO Shervin Pishevar promises, with increasingly rich features and better graphics.

The business plan? Advertising, of course, especially sponsorships, as well as the sale of virtual goods and premium offerings.

SGN’s other popular online games include FightClub, StreetRace, Jetman, Text Twirl and Free Gifts. It has 1.1 million daily active users mostly across Facebook, but also on Bebo, hi5, and MySpace.

In the space, its main competitor is Zynga (here is a post and video with its founder, Mark Pincus). Naturally, the two bicker back and forth in the blogosphere about size and quality of games.

But it seems to me that there is room for both, so the fighting seems like a lot of noisy, well, game-playing.

Here’s Pishevar talking about the sector: