The new campaign, created by Ogilvy Advertising, will launch in the US on 28 September, before being rolled out in the UK at the beginning of next month.
As part of the activity, Yahoo! will introduce a new slogan: "It's Y!ou", which encompasses the traditional Yahoo! logo and exclamation mark.
The first set of ads for the brand will also carry straplines such as: "The Internet has a new personality: Yours", and "The Internet is under new management: Yours", which the company hopes will reflect the central place that the internet now has in people's lives.
Elisa Steele, the executive vice president and chief marketing officer of Yahoo!, said: "Our vision is to be at the centre of people's lives, to be at the place where their world meets the larger world. Our new brand strategy shows our commitment to delivering personally relevant online experiences."