Joost, the online video site established by the founders of Skype, has raised $45m in funding from four venture capital and media groups, just a week after launching the service.

Sequioa Capital, which backed Yahoo, Google and YouTube; Index Ventures, an early investor in Skype; Li Ka-shing, the Hong Kong tycoon; and CBS, the US media group, have all taken “small minority” stakes in the start-up.