Twitter signs advertising deal with CBS The social media company, which is preparing to float for up to $15bn, announced the deal at Advertising Week in New York on Monday, in its first public pitch since it announced its plans to make an initial public offering. Companies that buy ad space on the network will also be invited to sponsor one-minute clips from CBS's shows, which will appear in the Twitter feeds of people who are likely to be interested. The audience will be chosen based on whether they have talked about the show on Twitter, or on other data that suggest they may be interested. Most social networks set themselves up as rivals to broadcasters, trying to persuade advertisers who plough their marketing budgets into traditional TV ads that the money would be better spent online. However, Twitter is doing the opposite and trying to woo advertisers by positioning itself as a tool that will help them make the most of traditional TV ads, which still suck up the lion's share of marketing dollars. Matthew Derella, Twitter's vice-president of sales, told the assembled marketing executives that the social network produced a "tidal wave" of valuable chatter that could be harnessed commercially to boost television shows, or the brands advertising around them. "If you're a network working to drive [audience] engagement and ratings, this is a very powerful opportunity," he said, delivering a well-rehearsed sales patter. This is word of mouth marketing at scale. The San Francisco-based company is under pressure to persuade the advertising industry that they need to pay for advertising on Twitter, rather than simply using the social network as a free platform for PR. Twitter has more than 200m users who collectively send more than 400m tweets a day, but it has sometimes struggled to monetise them effectively. It has stepped up efforts over the past two years, with the introduction of a few different advertising products, but it now faces unpreceneted pressure to demonstrate that it can persuade companies to pay for ads on Twitter, without bombarding users with ads in a way that will alienate them. Twitter's S-1, filed with the Securities and Exchange Commission ahead of the IPO, will remain sealed until early next month, but analysts estmate that the company will clock up more than $500m in revenues this year and double that figure in 2014.