The BBC has struck a content deal with YouTube, the web's most popular video sharing website, owned by Google.

Three YouTube channels, one for news and two for entertainment, will showcase short clips of BBC content.

The BBC hopes that the deal will help it reach YouTube's monthly audience of more than 70 million users and drive extra traffic to its own website.

In what could be the first steps to the BBC comericalising its web content, the corporation will also get a share of the advertising revenue generated by traffic to the new YouTube channels.

One of the BBC's two entertainment channels will be a "public service" proposition, featuring no advertising.

It will show clips like trailers and short features that add value - for example, video diaries of David Tennant showing viewers around the set of Dr Who or BBC correspondent Clive Myrie explaining how difficult it is to report from the streets of Baghdad.

"The channel's main purpose is to popularise current programming and drive traffic back to the BBC's own website, and point the audience to the BBC's pages, where they can watch or download programmes in full, once the BBC Trust approves the corporation's catch-up television proposal, called iPlayer", the BBC said.

BBC Worldwide will be the second entertainment channel will feature self-contained clips between 3 to 6 minutes long mining popular programmes in the BBC's archive. Excerpts from Top Gear, The Mighty Boosh and nature programmes presented by David Attenborough are top candidates for this channel.

Controversially, the BBC Worldwide page - adverts and all - can be seen in the UK.

Finally there will be a BBC News channel will show about 30 news clips per day. It will be advertising funded and similar to deals with Yahoo USA and Real Networks.

Because of the advertising, these clips can be seen outside the UK only.