On today's programme, Steve Hewlett discusses the influence of media agencies on broadcast networks. It follows comments by Channel 5 owner Richard Desmond, who has hit out at the power of Sir Martin Sorrell's UK media buying operation, Group M - the biggest player in the market. Joining Steve is chairman of Walker Media, Phil Georgiadis, and John McVay of Pact, the producer's alliance for cinema and television. And Steve asks Martin Bowley, the former chief executive of Carlton Media Sales, how the balance of power has shifted in the media buying world in recent years.In the week that's seen Twitter announce its intention to float, we ask how the model might have to change when under the scrutiny of investors. Keen tweeter and technology and digital media correspondent at the Telegraph Emma Barnett discusses how its coming-of-age may mark the start of some fundemental changes for the social networking site. And NPR media correspondent David Folkenflik talks about it's impact on global news. And we look at the language used by newspapers and TV reporters alike; 'journalese'. Robert Hutton, UK political correspondent for Bloomberg News has written a book, 'Romps, Tots and Boffins - The Strange Language of News'. He joins Steve to discuss his favourite examples. Producer: Katy Takatsuki.