Tidal TV, a startup trying to compete with Hulu and Joost with its offer of premium content, launched in beta last week. But just a couple days later, its CEO, Mollie Spilman, stepped down, for reasons that are not entirely clear.

Scott Ferber, co-founder and chairman of the company, is now in charge, though he is not formally the CEO. Ferber was previously co-founder and CEO of Advertising.com, where Spilman was chief sales and marketing officer. “She said, ‘Look you have the better and more experienced track record; the chance of success is higher if you run it,’” Ferber told NewTeeVee.

Spilman is heavily vested in Tidal TV, said Ferber, but she will no longer be involved in the operations of the company. If things are so amicable, I don’t quite understand why she wouldn’t just take a different role, but pressing the point didn’t get me a different answer.

Baltimore-based Tidal TV has 25 employees and has raised $15 million from New Enterprise Associates and Valhalla Partners.

The site has a slick interface, though I had some trouble finding some of the controls until Ferber walked me through it. It carries content from CBS, NBC News, National Geographic Channel, Scripps Networks, TV Guide Network and The Weather Channel. Tidal TV offers both linear-programmed channels and on-demand video in an attempt to “replicate the feeling of TV online,” said Ferber. In some cases content is available both linearly and on-demand; in other cases, just one way.

Ferber contended that Tidal TV’s edge over the competition is his track record in making money through advertising online, which he believes will help convince media companies to give the company their content. However, we shouldn’t forget that Hulu and Joost are part-owned by some of those media companies.

Two other video startup CEOs left their companies last week as well: Herb Scannell of Next New Networks and Bill Joll of On2.